Touch emulator: enables double tap support for pages similar to Chrome on Android.

content/browser/renderer_host/render_widget_host_impl.cc

 // Copyright (c) 2012 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.
 
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 
 #include <math.h>
 #include <set>
 #include <utility>
 
@@ skipping 1414 matching lines @@
   uint32 output_surface_id = get<0>(param);
   get<1>(param).AssignTo(frame.get());
   std::vector<IPC::Message> messages_to_deliver_with_frame;
   messages_to_deliver_with_frame.swap(get<2>(param));
 
   latency_tracker_.OnSwapCompositorFrame(&frame->metadata.latency_info);
 
   input_router_->OnViewUpdated(
       GetInputRouterViewFlagsFromCompositorFrameMetadata(frame->metadata));
 
+  if (touch_emulator_) {
+    touch_emulator_->SetDoubleTapSupportForPageEnabled(
+        IsMobileOptimizedFrame(frame->metadata));
+  }
+
   if (view_) {
     view_->OnSwapCompositorFrame(output_surface_id, frame.Pass());
     view_->DidReceiveRendererFrame();
   } else {
     cc::CompositorFrameAck ack;
     if (frame->gl_frame_data) {
       ack.gl_frame_data = frame->gl_frame_data.Pass();
       ack.gl_frame_data->sync_point = 0;
     } else if (frame->delegated_frame_data) {
       cc::TransferableResource::ReturnResources(
@@ skipping 718 matching lines @@
 }
 #endif
 
 SkColorType RenderWidgetHostImpl::PreferredReadbackFormat() {
   if (view_)
     return view_->PreferredReadbackFormat();
   return kN32_SkColorType;
 }
 
 }  // namespace content