Fix browser crash on shutdown when ProfileImplIOData::Handle::Init is…

…n't called.

With ephemeral profiles, in some cases, a Handle will be created and destroyed
without being initialized. Root cause of why the object is created is still not
known, but this change prevents the crash from occurring.

BUG=478215

Review URL: https://codereview.chromium.org/1072143003

Cr-Commit-Position: refs/heads/master@{#326371}
(cherry picked from commit 08f40f1)

Review URL: https://codereview.chromium.org/1087903003

Cr-Commit-Position: refs/branch-heads/2357@{#223}
Cr-Branched-From: 59d4494-refs/heads/master@{#323860}

chrome/browser/profiles/profile_impl_io_data.cc

@@ -132,7 +132,11 @@ ProfileImplIOData::Handle::~Handle() {
   if (io_data_->http_server_properties_manager_)
     io_data_->http_server_properties_manager_->ShutdownOnPrefThread();
 
-  io_data_->data_reduction_proxy_io_data()->ShutdownOnUIThread();
+  // io_data_->data_reduction_proxy_io_data() might be NULL if Init() was
+  // never called.
+  if (io_data_->data_reduction_proxy_io_data())
+    io_data_->data_reduction_proxy_io_data()->ShutdownOnUIThread();
+
   io_data_->ShutdownOnUIThread(GetAllContextGetters().Pass());
 }