Implementation of device metrics emulation in render view.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
===================================================================
--- content/browser/renderer_host/render_widget_host_view_aura.cc	(revision 221161)
+++ content/browser/renderer_host/render_widget_host_view_aura.cc	(working copy)
@@ -805,6 +805,8 @@
 
 void RenderWidgetHostViewAura::MaybeCreateResizeLock() {
   gfx::Size desired_size = window_->bounds().size();
+  if (!expected_rendered_size_.IsEmpty())
+    desired_size = expected_rendered_size_;
   if (!host_->should_auto_resize() &&
       !resize_lock_.get() &&
       desired_size != current_frame_size_ &&
@@ -2002,6 +2004,10 @@
     touch_editing_client_->GestureEventAck(gesture_event_type);
 }
 
+void RenderWidgetHostViewAura::SetExpectedRenderedSize(const gfx::Size& size) {
+  expected_rendered_size_ = size;
+}
+
 void RenderWidgetHostViewAura::ProcessAckedTouchEvent(
     const TouchEventWithLatencyInfo& touch, InputEventAckState ack_result) {
   ScopedVector<ui::TouchEvent> events;