diff --git a/blink/renderer/bindings/generated_in_core.gni b/blink/renderer/bindings/generated_in_core.gni
index 7c021ad4c211..0763ae563f5e 100644
--- a/blink/renderer/bindings/generated_in_core.gni
+++ b/blink/renderer/bindings/generated_in_core.gni
@@ -301,8 +301,6 @@ generated_dictionary_sources_in_core = [
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_scroll_to_options.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_security_policy_violation_event_init.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_security_policy_violation_event_init.h",
-  "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_set_inner_html_options.cc",
-  "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_set_inner_html_options.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_shadow_root_init.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_shadow_root_init.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_stream_pipe_options.cc",
diff --git a/blink/renderer/bindings/idl_in_core.gni b/blink/renderer/bindings/idl_in_core.gni
index 9a546b39ac98..3aae862c30e1 100644
--- a/blink/renderer/bindings/idl_in_core.gni
+++ b/blink/renderer/bindings/idl_in_core.gni
@@ -162,7 +162,6 @@ static_idl_files_in_core = get_path_info(
           "//third_party/blink/renderer/core/dom/pointer_lock_options.idl",
           "//third_party/blink/renderer/core/dom/processing_instruction.idl",
           "//third_party/blink/renderer/core/dom/range.idl",
-          "//third_party/blink/renderer/core/dom/set_inner_html_options.idl",
           "//third_party/blink/renderer/core/dom/shadow_root.idl",
           "//third_party/blink/renderer/core/dom/shadow_root_init.idl",
           "//third_party/blink/renderer/core/dom/static_range.idl",
diff --git a/blink/renderer/core/core_idl_files.gni b/blink/renderer/core/core_idl_files.gni
index eec15ef4af67..9ae17527f5d1 100644
--- a/blink/renderer/core/core_idl_files.gni
+++ b/blink/renderer/core/core_idl_files.gni
@@ -652,7 +652,6 @@ core_dictionary_idl_files =
                     "dom/idle_request_options.idl",
                     "dom/mutation_observer_init.idl",
                     "dom/pointer_lock_options.idl",
-                    "dom/set_inner_html_options.idl",
                     "dom/shadow_root_init.idl",
                     "dom/events/add_event_listener_options.idl",
                     "dom/events/custom_event_init.idl",
diff --git a/blink/renderer/core/dom/element.cc b/blink/renderer/core/dom/element.cc
index 94eae66b52ec..16c47ad8a6a2 100644
--- a/blink/renderer/core/dom/element.cc
+++ b/blink/renderer/core/dom/element.cc
@@ -44,7 +44,6 @@
 #include "third_party/blink/renderer/bindings/core/v8/v8_pointer_lock_options.h"
 #include "third_party/blink/renderer/bindings/core/v8/v8_scroll_into_view_options.h"
 #include "third_party/blink/renderer/bindings/core/v8/v8_scroll_to_options.h"
-#include "third_party/blink/renderer/bindings/core/v8/v8_set_inner_html_options.h"
 #include "third_party/blink/renderer/bindings/core/v8/v8_shadow_root_init.h"
 #include "third_party/blink/renderer/core/accessibility/ax_context.h"
 #include "third_party/blink/renderer/core/accessibility/ax_object_cache.h"
@@ -4467,13 +4466,11 @@ String Element::outerHTML() const {
 }
 
 void Element::SetInnerHTMLInternal(const String& html,
-                                   const SetInnerHTMLOptions* options,
+                                   bool include_shadow_roots,
                                    ExceptionState& exception_state) {
   if (html.IsEmpty() && !HasNonInBodyInsertionMode()) {
     setTextContent(html);
   } else {
-    bool include_shadow_roots =
-        options->hasIncludeShadowRoots() && options->includeShadowRoots();
     if (DocumentFragment* fragment = CreateFragmentForInnerOuterHTML(
             html, this, kAllowScriptingContent, "innerHTML",
             include_shadow_roots, exception_state)) {
@@ -4493,16 +4490,13 @@ void Element::SetInnerHTMLInternal(const String& html,
 void Element::setInnerHTML(const String& html,
                            ExceptionState& exception_state) {
   probe::BreakableLocation(GetExecutionContext(), "Element.setInnerHTML");
-  const SetInnerHTMLOptions options;
-  SetInnerHTMLInternal(html, &options, exception_state);
+  SetInnerHTMLInternal(html, /*include_shadow_roots=*/false, exception_state);
 }
 
-void Element::setInnerHTMLWithOptions(const String& html,
-                                      const SetInnerHTMLOptions* options,
-                                      ExceptionState& exception_state) {
-  DCHECK(RuntimeEnabledFeatures::DeclarativeShadowDOMEnabled(
-      GetExecutionContext()));
-  SetInnerHTMLInternal(html, options, exception_state);
+void Element::setInnerHTMLWithDeclarativeShadowDOMForTesting(
+    const String& html) {
+  SetInnerHTMLInternal(html, /*include_shadow_roots=*/true,
+                       ASSERT_NO_EXCEPTION);
 }
 
 String Element::getInnerHTML(const GetInnerHTMLOptions* options) const {
diff --git a/blink/renderer/core/dom/element.h b/blink/renderer/core/dom/element.h
index d99e36e734ed..528fcabcbedf 100644
--- a/blink/renderer/core/dom/element.h
+++ b/blink/renderer/core/dom/element.h
@@ -66,7 +66,6 @@ class ExceptionState;
 class FloatQuad;
 class FloatSize;
 class FocusOptions;
-class SetInnerHTMLOptions;
 class GetInnerHTMLOptions;
 class HTMLTemplateElement;
 class Image;
@@ -698,9 +697,7 @@ class CORE_EXPORT Element : public ContainerNode, public Animatable {
   String innerHTML() const;
   String outerHTML() const;
   void setInnerHTML(const String&, ExceptionState& = ASSERT_NO_EXCEPTION);
-  void setInnerHTMLWithOptions(const String&,
-                               const SetInnerHTMLOptions*,
-                               ExceptionState& = ASSERT_NO_EXCEPTION);
+  void setInnerHTMLWithDeclarativeShadowDOMForTesting(const String& html);
   String getInnerHTML(const GetInnerHTMLOptions* options) const;
   void setOuterHTML(const String&, ExceptionState& = ASSERT_NO_EXCEPTION);
 
@@ -1190,7 +1187,7 @@ class CORE_EXPORT Element : public ContainerNode, public Animatable {
                                                         const AtomicString&);
 
   void SetInnerHTMLInternal(const String&,
-                            const SetInnerHTMLOptions*,
+                            bool include_shadow_roots,
                             ExceptionState&);
 
   ElementRareData* GetElementRareData() const;
diff --git a/blink/renderer/core/dom/element.idl b/blink/renderer/core/dom/element.idl
index 5ddc26a59d07..cd37b91d5400 100644
--- a/blink/renderer/core/dom/element.idl
+++ b/blink/renderer/core/dom/element.idl
@@ -96,8 +96,7 @@ callback ScrollStateCallback = void (ScrollState scrollState);
     [Affects=Nothing, CEReactions, CustomElementCallbacks, RaisesException=Setter] attribute [TreatNullAs=EmptyString, StringContext=TrustedHTML] DOMString outerHTML;
     [CEReactions, CustomElementCallbacks, RaisesException] void insertAdjacentHTML(DOMString position, HTMLString text);
 
-    // Declarative Shadow DOM setInnerHTML/getInnerHTML() functions.
-    [Affects=Nothing, RuntimeEnabled=DeclarativeShadowDOM, RuntimeCallStatsCounter=ElementSetInnerHTML, RaisesException, ImplementedAs=setInnerHTMLWithOptions] void setInnerHTML(HTMLString html, optional SetInnerHTMLOptions options = {});
+    // Declarative Shadow DOM getInnerHTML() function.
     [Affects=Nothing, RuntimeEnabled=DeclarativeShadowDOM, RuntimeCallStatsCounter=ElementGetInnerHTML] HTMLString getInnerHTML(optional GetInnerHTMLOptions options = {});
 
     // Pointer Lock
diff --git a/blink/renderer/core/dom/set_inner_html_options.idl b/blink/renderer/core/dom/set_inner_html_options.idl
deleted file mode 100644
index 6e6d5961e567..000000000000
--- a/blink/renderer/core/dom/set_inner_html_options.idl
+++ /dev/null
@@ -1,7 +0,0 @@
-// Copyright 2020 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-dictionary SetInnerHTMLOptions {
-  boolean includeShadowRoots = false;
-};
diff --git a/blink/renderer/core/dom/shadow_root.cc b/blink/renderer/core/dom/shadow_root.cc
index b690005251a5..b3086ac50bdb 100644
--- a/blink/renderer/core/dom/shadow_root.cc
+++ b/blink/renderer/core/dom/shadow_root.cc
@@ -28,7 +28,6 @@
 
 #include "third_party/blink/public/platform/platform.h"
 #include "third_party/blink/renderer/bindings/core/v8/v8_get_inner_html_options.h"
-#include "third_party/blink/renderer/bindings/core/v8/v8_set_inner_html_options.h"
 #include "third_party/blink/renderer/core/css/resolver/style_resolver.h"
 #include "third_party/blink/renderer/core/css/style_change_reason.h"
 #include "third_party/blink/renderer/core/css/style_engine.h"
@@ -133,32 +132,15 @@ String ShadowRoot::getInnerHTML(const GetInnerHTMLOptions* options) const {
       include_closed_roots);
 }
 
-void ShadowRoot::SetInnerHTMLInternal(const String& html,
-                                      const SetInnerHTMLOptions* options,
-                                      ExceptionState& exception_state) {
-  bool include_shadow_roots =
-      options->hasIncludeShadowRoots() && options->includeShadowRoots();
+void ShadowRoot::setInnerHTML(const String& html,
+                              ExceptionState& exception_state) {
   if (DocumentFragment* fragment = CreateFragmentForInnerOuterHTML(
           html, &host(), kAllowScriptingContent, "innerHTML",
-          include_shadow_roots, exception_state)) {
+          /*include_shadow_roots=*/false, exception_state)) {
     ReplaceChildrenWithFragment(this, fragment, exception_state);
   }
 }
 
-void ShadowRoot::setInnerHTML(const String& html,
-                              ExceptionState& exception_state) {
-  const SetInnerHTMLOptions options;
-  SetInnerHTMLInternal(html, &options, exception_state);
-}
-
-void ShadowRoot::setInnerHTMLWithOptions(const String& html,
-                                         const SetInnerHTMLOptions* options,
-                                         ExceptionState& exception_state) {
-  DCHECK(RuntimeEnabledFeatures::DeclarativeShadowDOMEnabled(
-      GetExecutionContext()));
-  SetInnerHTMLInternal(html, options, exception_state);
-}
-
 void ShadowRoot::RebuildLayoutTree(WhitespaceAttacher& whitespace_attacher) {
   DCHECK(!NeedsReattachLayoutTree());
   DCHECK(!ChildNeedsReattachLayoutTree());
diff --git a/blink/renderer/core/dom/shadow_root.h b/blink/renderer/core/dom/shadow_root.h
index e46afe262bdb..7fedf6b9e1c2 100644
--- a/blink/renderer/core/dom/shadow_root.h
+++ b/blink/renderer/core/dom/shadow_root.h
@@ -40,7 +40,6 @@ namespace blink {
 
 class Document;
 class ExceptionState;
-class SetInnerHTMLOptions;
 class GetInnerHTMLOptions;
 class ShadowRootV0;
 class SlotAssignment;
@@ -141,9 +140,6 @@ class CORE_EXPORT ShadowRoot final : public DocumentFragment, public TreeScope {
   String innerHTML() const;
   String getInnerHTML(const GetInnerHTMLOptions* options) const;
   void setInnerHTML(const String&, ExceptionState& = ASSERT_NO_EXCEPTION);
-  void setInnerHTMLWithOptions(const String&,
-                               const SetInnerHTMLOptions*,
-                               ExceptionState& = ASSERT_NO_EXCEPTION);
 
   Node* Clone(Document&, CloneChildrenFlag) const override;
 
@@ -194,10 +190,6 @@ class CORE_EXPORT ShadowRoot final : public DocumentFragment, public TreeScope {
 
   SlotAssignment& EnsureSlotAssignment();
 
-  void SetInnerHTMLInternal(const String&,
-                            const SetInnerHTMLOptions*,
-                            ExceptionState&);
-
   void AddChildShadowRoot() { ++child_shadow_root_count_; }
   void RemoveChildShadowRoot() {
     DCHECK_GT(child_shadow_root_count_, 0u);
diff --git a/blink/renderer/core/dom/shadow_root.idl b/blink/renderer/core/dom/shadow_root.idl
index 8039552be647..f0a57be34470 100644
--- a/blink/renderer/core/dom/shadow_root.idl
+++ b/blink/renderer/core/dom/shadow_root.idl
@@ -36,8 +36,7 @@ interface ShadowRoot : DocumentFragment {
     readonly attribute boolean delegatesFocus;
     [RuntimeEnabled=ManualSlotting] readonly attribute SlotAssignmentMode slotAssignment;
 
-    // Declarative Shadow DOM setInnerHTML/getInnerHTML() functions.
-    [Affects=Nothing, RuntimeEnabled=DeclarativeShadowDOM, RuntimeCallStatsCounter=ElementSetInnerHTML, RaisesException, ImplementedAs=setInnerHTMLWithOptions] void setInnerHTML(HTMLString html, optional SetInnerHTMLOptions options = {});
+    // Declarative Shadow DOM getInnerHTML() function.
     [Affects=Nothing, RuntimeEnabled=DeclarativeShadowDOM, RuntimeCallStatsCounter=ElementGetInnerHTML] HTMLString getInnerHTML(optional GetInnerHTMLOptions options = {});
 };
 
diff --git a/blink/renderer/core/dom/slot_assignment_test.cc b/blink/renderer/core/dom/slot_assignment_test.cc
index 9e52fd4a1c70..6e60db473eef 100644
--- a/blink/renderer/core/dom/slot_assignment_test.cc
+++ b/blink/renderer/core/dom/slot_assignment_test.cc
@@ -5,7 +5,6 @@
 #include "third_party/blink/renderer/core/dom/flat_tree_traversal.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
-#include "third_party/blink/renderer/bindings/core/v8/v8_set_inner_html_options.h"
 #include "third_party/blink/renderer/core/dom/document.h"
 #include "third_party/blink/renderer/core/dom/element.h"
 #include "third_party/blink/renderer/core/dom/node.h"
@@ -70,9 +69,7 @@ void SlotAssignmentTest::SetUp() {
 
 void SlotAssignmentTest::SetBody(const char* html) {
   Element* body = GetDocument().body();
-  SetInnerHTMLOptions options;
-  options.setIncludeShadowRoots(true);
-  body->setInnerHTMLWithOptions(String::FromUTF8(html), &options);
+  body->setInnerHTMLWithDeclarativeShadowDOMForTesting(String::FromUTF8(html));
   RemoveWhiteSpaceOnlyTextNode(*body);
 }
 
diff --git a/blink/renderer/platform/bindings/runtime_call_stats.h b/blink/renderer/platform/bindings/runtime_call_stats.h
index 96136b348f6d..99a79bb2eb23 100644
--- a/blink/renderer/platform/bindings/runtime_call_stats.h
+++ b/blink/renderer/platform/bindings/runtime_call_stats.h
@@ -250,7 +250,6 @@ class PLATFORM_EXPORT RuntimeCallStats {
 #define CALLBACK_COUNTERS(V)                       \
   BINDINGS_METHOD(V, ElementGetBoundingClientRect) \
   BINDINGS_METHOD(V, ElementGetInnerHTML)          \
-  BINDINGS_METHOD(V, ElementSetInnerHTML)          \
   BINDINGS_METHOD(V, EventTargetDispatchEvent)     \
   BINDINGS_METHOD(V, HTMLElementClick)             \
   BINDINGS_METHOD(V, NodeAppendChild)              \
diff --git a/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-attachment.tentative.html b/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-attachment.tentative.html
index c4a35d341c1f..b9033f599242 100644
--- a/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-attachment.tentative.html
+++ b/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-attachment.tentative.html
@@ -5,6 +5,7 @@
 <script src='/resources/testharness.js'></script>
 <script src='/resources/testharnessreport.js'></script>
 <script src='../resources/shadow-dom-utils.js'></script>
+<script src="support/helpers.js"></script>
 
 <script>
 const shadowContent = '<span>Shadow tree</span><slot></slot>';
@@ -18,7 +19,7 @@
   const declarativeString = `<${elementType} id=theelement>${getDeclarativeContent(mode, delegatesFocus)}
      <span class='lightdom'>${lightDomTextContent}</span></${elementType}>`;
   const wrapper = document.createElement('div');
-  wrapper.setInnerHTML(declarativeString, {includeShadowRoots: true});
+  setInnerHTML(wrapper, declarativeString);
   const element = wrapper.querySelector('#theelement');
   return {wrapper: wrapper, element: element};
 }
diff --git a/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-basic.tentative.html b/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-basic.tentative.html
index 6e3c16a9d82d..a03743e44ffd 100644
--- a/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-basic.tentative.html
+++ b/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-basic.tentative.html
@@ -5,6 +5,7 @@
 <link rel="help" href="https://github.com/whatwg/dom/issues/831">
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
+<script src="support/helpers.js"></script>
 
 <div id="host" style="display:none">
   <template shadowroot="open">
@@ -32,14 +33,14 @@
 
 test(() => {
   const div = document.createElement('div');
-  div.setInnerHTML(`
+  setInnerHTML(div,`
     <div id="host">
       <template shadowroot="open">
         <slot id="s1" name="slot1"></slot>
       </template>
       <div id="c1" slot="slot1"></div>
     </div>
-    `, {includeShadowRoots: true});
+    `);
   const host = div.querySelector('#host');
   const c1 = host.querySelector('#c1');
   assert_true(!!c1);
@@ -53,12 +54,12 @@
 
 test(() => {
   const div = document.createElement('div');
-  div.setInnerHTML(`
+  setInnerHTML(div,`
     <div id="host">
       <template shadowroot="invalid">
       </template>
     </div>
-    `, {includeShadowRoots: true});
+    `);
   const host = div.querySelector('#host');
   assert_equals(host.shadowRoot, null, "Shadow root was found");
   const tmpl = host.querySelector('template');
@@ -69,12 +70,12 @@
 
 test(() => {
   const div = document.createElement('div');
-  div.setInnerHTML(`
+  setInnerHTML(div,`
     <div id="host">
       <template shadowroot="closed">
       </template>
     </div>
-    `, {includeShadowRoots: true});
+    `);
   const host = div.querySelector('#host');
   assert_equals(host.shadowRoot, null, "Closed shadow root");
   assert_equals(host.querySelector('template'), null, "No template - converted to shadow root");
@@ -82,12 +83,12 @@
 
 test(() => {
   const div = document.createElement('div');
-  div.setInnerHTML(`
+  setInnerHTML(div,`
     <div id="host">
       <template shadowroot="open">
         <slot id="s1" name="slot1"></slot>
     </div>
-    `, {includeShadowRoots: true});
+    `);
   const host = div.querySelector('#host');
   assert_equals(host.querySelector('#s1'), null, "Should be inside shadow root");
   assert_equals(host.querySelector('template'), null, "No leftover template node");
@@ -98,35 +99,25 @@
 
 test(() => {
   const div = document.createElement('div');
-  div.setInnerHTML(`
+  setInnerHTML(div,`
     <div id="host">
       <template shadowroot="open" shadowrootdelegatesfocus>
       </template>
     </div>
-    `, {includeShadowRoots: true});
+    `);
   var host = div.querySelector('#host');
   assert_true(!!host.shadowRoot,"No shadow root found");
   assert_true(host.shadowRoot.delegatesFocus,"delegatesFocus should be true");
-  div.setInnerHTML(`
+  setInnerHTML(div,`
     <div id="host">
       <template shadowroot="open">
       </template>
     </div>
-    `, {includeShadowRoots: true});
+    `);
   host = div.querySelector('#host');
   assert_true(!!host.shadowRoot,"No shadow root found");
   assert_false(host.shadowRoot.delegatesFocus,"delegatesFocus should be false without the shadowrootdelegatesfocus attribute");
 }, 'Declarative Shadow DOM: delegates focus attribute');
-
-test(() => {
-  const host = document.createElement('div');
-  // Root element of setInnerHTML is a <template shadowroot>:
-  host.setInnerHTML('<template shadowroot=open></template>', {allowShadowRoot: true});
-  assert_equals(host.shadowRoot, null, "Shadow root should not be present");
-  const tmpl = host.querySelector('template');
-  assert_true(!!tmpl,"Template should still be present");
-  assert_equals(tmpl.getAttribute('shadowroot'),"open","'shadowroot' attribute should still be present");
-}, 'Declarative Shadow DOM: setInnerHTML root element');
 </script>
 
 <div id="multi-host" style="display:none">
diff --git a/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-opt-in.tentative.html b/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-opt-in.tentative.html
index 2d6bf5f3f2d9..d1fd9fc448a2 100644
--- a/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-opt-in.tentative.html
+++ b/blink/web_tests/external/wpt/shadow-dom/declarative/declarative-shadow-dom-opt-in.tentative.html
@@ -5,6 +5,7 @@
 <link rel="help" href="https://github.com/whatwg/dom/issues/831">
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
+<script src='../resources/shadow-dom-utils.js'></script>
 
 <body>
 <style>
@@ -58,56 +59,40 @@
   assert_dsd(div,true);
 }, 'Non-fragment parsing needs no opt-in');
 
-test(() => {
-  const div = document.createElement('div');
-  div.innerHTML = content;
-  assert_dsd(div,false);
-}, 'innerHTML on element - disallowed');
-
-test(() => {
-  const div = document.createElement('div');
-  div.setInnerHTML(content);
-  assert_dsd(div,false);
-  div.setInnerHTML(content, {includeShadowRoots: false});
-  assert_dsd(div,false);
-  div.setInnerHTML(content, {includeShadowRoots: true});
-  assert_dsd(div,true);
-}, 'setInnerHTML on element');
-
-test(() => {
-  const templateContent = `<template id=tmpl>${content}</template>`;
-  const div = document.createElement('div');
-  div.innerHTML = templateContent;
-  assert_dsd(div.querySelector('#tmpl').content,false);
-  div.setInnerHTML(templateContent, {includeShadowRoots: true});
-  assert_dsd(div.querySelector('#tmpl').content,true);
-}, 'setInnerHTML on element, with nested template content');
+const noChildElements = ['iframe','noscript','script','select','style','textarea','title','colgroup'];
+const elements = HTML5_ELEMENT_NAMES.filter(el => !noChildElements.includes(el));
+for (let elementName of elements) {
+  var t = test(function() {
+    const el1 = document.createElement(elementName);
+    el1.innerHTML = content;
+    assert_dsd(el1,false);
+
+    const templateContent = `<template id=tmpl>${content}</template>`;
+    const el2 = document.createElement('div');
+    el2.innerHTML = templateContent;
+    assert_dsd(el2.querySelector('#tmpl').content,false);
+  }, `innerHTML on a <${elementName}>`);
+}
 
 test(() => {
   const temp = document.createElement('template');
   temp.innerHTML = content;
   assert_dsd(temp.content,false, 'innerHTML should not allow declarative shadow content');
-  temp.setInnerHTML(content, {includeShadowRoots: true});
-  assert_dsd(temp.content,true, 'setInnerHTML should allow declarative shadow content if enabled');
-}, 'setInnerHTML on template');
+}, 'innerHTML on template');
 
 test(() => {
   const templateContent = `<template id=tmpl>${content}</template>`;
   const temp = document.createElement('template');
   temp.innerHTML = templateContent;
   assert_dsd(temp.content.querySelector('#tmpl').content,false);
-  temp.setInnerHTML(templateContent, {includeShadowRoots: true});
-  assert_dsd(temp.content.querySelector('#tmpl').content,true);
-}, 'setInnerHTML on template, with nested template content');
+}, 'innerHTML on template, with nested template content');
 
 test(() => {
   const div = document.createElement('div');
   const shadow = div.attachShadow({mode: 'open'});
   shadow.innerHTML = content;
   assert_dsd(shadow,false);
-  shadow.setInnerHTML(content, {includeShadowRoots: true});
-  assert_dsd(shadow,true);
-}, 'setInnerHTML on shadowRoot');
+}, 'innerHTML on shadowRoot');
 
 test(() => {
   const parser = new DOMParser();
@@ -123,9 +108,7 @@
   const doc = document.implementation.createHTMLDocument('');
   doc.body.innerHTML = content;
   assert_dsd(doc.body,false);
-  doc.body.setInnerHTML(content, {includeShadowRoots: true});
-  assert_dsd(doc.body,true);
-}, 'createHTMLDocument with setInnerHTML');
+}, 'createHTMLDocument with innerHTML - not supported');
 
 test(() => {
   const doc = document.implementation.createHTMLDocument('');
@@ -145,7 +128,7 @@
   client.open("GET", `data:text/html,${content}`);
   client.responseType = 'document';
   client.send();
-}, 'XMLHttpRequest, disabled');
+}, 'XMLHttpRequest - not supported');
 
 test(() => {
   const div = document.createElement('div');
diff --git a/blink/web_tests/external/wpt/shadow-dom/declarative/setinnerhtml.tentative.html b/blink/web_tests/external/wpt/shadow-dom/declarative/setinnerhtml.tentative.html
deleted file mode 100644
index c65bf04a06c9..000000000000
--- a/blink/web_tests/external/wpt/shadow-dom/declarative/setinnerhtml.tentative.html
+++ /dev/null
@@ -1,48 +0,0 @@
-<!DOCTYPE html>
-<title>getInnerHTML </title>
-<link rel='author' title='Mason Freed' href='mailto:masonfreed@chromium.org'>
-<link rel='help' href='https://github.com/whatwg/dom/issues/831'>
-<script src='/resources/testharness.js'></script>
-<script src='/resources/testharnessreport.js'></script>
-<script src='../resources/shadow-dom-utils.js'></script>
-
-<body>
-<script>
-function testElementType(allowsShadowDom, elementType, applyToShadow) {
-  const t = test(t => {
-    // Create and attach element
-    let wrapper;
-    if (applyToShadow) {
-      const host = document.createElement('div');
-      t.add_cleanup(function() { host.remove(); });
-      document.body.appendChild(host);
-      wrapper = host.attachShadow({mode: 'open'});
-    } else {
-      wrapper = document.createElement('div');
-      t.add_cleanup(function() { wrapper.remove(); });
-      document.body.appendChild(wrapper);
-    }
-    const html = `<${elementType}><template shadowroot="open"><slot></slot></template><span></span></${elementType}>`;
-    wrapper.setInnerHTML(html, {includeShadowRoots: true});
-    if (allowsShadowDom) {
-      // Retrieve shadow root
-      assert_true(!!wrapper.firstElementChild.shadowRoot,'No shadow root found');
-    } else {
-      const leftover = wrapper.firstElementChild.firstElementChild;
-      assert_true(wrapper.firstElementChild.childElementCount == 0 || leftover instanceof HTMLTemplateElement,'Template should be left over (or no children)');
-    }
-  }, `${applyToShadow ? 'ShadowRoot' : 'Element'}.setInnerHTML() on <${elementType}>${allowsShadowDom ? `, with declarative Shadow DOM.` : ''}`);
-}
-
-function runAllTests() {
-  const allElements = [...HTML5_ELEMENT_NAMES, 'htmlunknown'].filter(item => item !== 'body');
-  const safelisted = ATTACHSHADOW_SAFELISTED_ELEMENTS;
-  for (const elementName of allElements) {
-    for (const applyToShadow of [false, true]) {
-      testElementType(safelisted.includes(elementName), elementName, applyToShadow);
-    }
-  }
-}
-
-runAllTests();
-</script>
diff --git a/blink/web_tests/external/wpt/shadow-dom/declarative/support/helpers.js b/blink/web_tests/external/wpt/shadow-dom/declarative/support/helpers.js
new file mode 100644
index 000000000000..70808e8db7b1
--- /dev/null
+++ b/blink/web_tests/external/wpt/shadow-dom/declarative/support/helpers.js
@@ -0,0 +1,4 @@
+function setInnerHTML(el,content) {
+  const fragment = (new DOMParser()).parseFromString(`<pre>${content}</pre>`, 'text/html', {includeShadowRoots: true});
+  el.replaceChildren(...fragment.body.firstChild.childNodes);
+}
diff --git a/blink/web_tests/http/tests/origin_trials/webexposed/declarative-shadow-dom-origin-trial-interfaces.html b/blink/web_tests/http/tests/origin_trials/webexposed/declarative-shadow-dom-origin-trial-interfaces.html
index 41c410a07d1c..aa8028b7f0df 100644
--- a/blink/web_tests/http/tests/origin_trials/webexposed/declarative-shadow-dom-origin-trial-interfaces.html
+++ b/blink/web_tests/http/tests/origin_trials/webexposed/declarative-shadow-dom-origin-trial-interfaces.html
@@ -9,12 +9,18 @@
 <script src="/resources/testharnessreport.js"></script>
 <script>
 test(t => {
-  // Basic feature detection
   assert_true(HTMLTemplateElement.prototype.hasOwnProperty("shadowRoot"),'Unable to feature detect');
-  // Basic feature use
-  const div = document.createElement('div');
-  div.setInnerHTML('<div id="host"><template shadowroot="open"></template></div>', {includeShadowRoots: true});
-  const host = div.querySelector('#host');
+}, 'Declarative Shadow DOM feature detection for origin-trial enabled document.');
+</script>
+
+<div id=host>
+	<template shadowroot="open"></template>
+</div>
+
+<script>
+test(t => {
+  const host = document.querySelector('#host');
+  assert_true(!!host,"Unable to locate host");
   assert_true(!!host.shadowRoot,"No shadow root found");
 }, 'Declarative Shadow DOM enabled for origin-trial enabled document.');
 </script>
diff --git a/blink/web_tests/webexposed/element-instance-property-listing-expected.txt b/blink/web_tests/webexposed/element-instance-property-listing-expected.txt
index ae00245cbbbb..efca04c1e353 100644
--- a/blink/web_tests/webexposed/element-instance-property-listing-expected.txt
+++ b/blink/web_tests/webexposed/element-instance-property-listing-expected.txt
@@ -308,7 +308,6 @@ namespace http://www.w3.org/1999/xhtml
     property setAttributeNS
     property setAttributeNode
     property setAttributeNodeNS
-    property setInnerHTML
     property setPointerCapture
     property shadowRoot
     property slot
@@ -1494,7 +1493,6 @@ namespace http://www.w3.org/2000/svg
     property setAttributeNS
     property setAttributeNode
     property setAttributeNodeNS
-    property setInnerHTML
     property setPointerCapture
     property shadowRoot
     property slot
diff --git a/blink/web_tests/webexposed/global-interface-listing-expected.txt b/blink/web_tests/webexposed/global-interface-listing-expected.txt
index 43a230b6d225..0df2bdc2213a 100644
--- a/blink/web_tests/webexposed/global-interface-listing-expected.txt
+++ b/blink/web_tests/webexposed/global-interface-listing-expected.txt
@@ -2140,7 +2140,6 @@ interface Element : Node
     method setAttributeNS
     method setAttributeNode
     method setAttributeNodeNS
-    method setInnerHTML
     method setPointerCapture
     method toggleAttribute
     method webkitMatchesSelector
@@ -8066,7 +8065,6 @@ interface ShadowRoot : DocumentFragment
     method getAnimations
     method getInnerHTML
     method getSelection
-    method setInnerHTML
     setter adoptedStyleSheets
     setter fullscreenElement
     setter innerHTML