bluetooth: FakeBluetoothChooser stub impl.

This change adds a new FakeBluetoothChooser interface stub to expand on.
The design for this class is detailed in the following document:
https://docs.google.com/document/d/1XFl_4ZAgO8ddM6U53A9AfUuZeWgJnlYD5wtbXqEpzeg

BUG=719827

Change-Id: I34169ce62dd5b35796639b7643d899b8315cc4c7

bluetooth/resources/bluetooth-helpers.js

@@ -43,6 +43,7 @@ function performChromiumSetup() {
     `${prefix}/uuid.mojom.js`,
     `${prefix}/fake_bluetooth.mojom.js`,
     `${prefix}/web-bluetooth-test.js`,
+    'file:///gen/content/shell/common/layout_test/fake_bluetooth_chooser.mojom.js',
   ].concat(extra))
       // Call setBluetoothFakeAdapter() to clean up any fake adapters left over
       // by legacy tests.

resources/chromium/web-bluetooth-test.js

@@ -65,7 +65,7 @@ class FakeBluetooth {
   constructor() {
     this.fake_bluetooth_ptr_ = new bluetooth.mojom.FakeBluetoothPtr();
     Mojo.bindInterface(bluetooth.mojom.FakeBluetooth.name,
-        mojo.makeRequest(this.fake_bluetooth_ptr_).handle, "process");
+        mojo.makeRequest(this.fake_bluetooth_ptr_).handle, 'process');
   }
 
   // Set it to indicate whether the platform supports BLE. For example,
@@ -102,6 +102,15 @@ class FakeBluetooth {
     let {consumed} = await this.fake_bluetooth_ptr_.allResponsesConsumed();
     return consumed;
   }
+
+  // Returns a promise that resolves with a FakeChooser that clients can use to
+  // simulate chooser events.
+  async getManualChooser() {
+    if (typeof this.fake_chooser_ === 'undefined') {
+      this.fake_chooser_ = new FakeChooser();
+    }
+    return this.fake_chooser_;
+  }
 }
 
 // FakeCentral allows clients to simulate events that a device in the
@@ -437,6 +446,17 @@ class FakeRemoteGATTDescriptor {
   }
 }
 
+// FakeChooser allows clients to simulate events that a user would trigger when
+// using the Bluetooth chooser, and monitor the events that are produced.
+class FakeChooser {
+  constructor() {
+    this.fake_bluetooth_chooser_ptr_ =
+        new content.mojom.FakeBluetoothChooserPtr();
+    Mojo.bindInterface(content.mojom.FakeBluetoothChooser.name,
+        mojo.makeRequest(this.fake_bluetooth_chooser_ptr_).handle, 'process');
+  }
+}
+
 // If this line fails, it means that current environment does not support the
 // Web Bluetooth Test API.
 try {