Cross-process frames should be notified of device scale factor changes.

content/browser/renderer_host/render_widget_host_delegate.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 "build/build_config.h"
 #include "content/browser/renderer_host/render_widget_host_delegate.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace content {
 
+double RenderWidgetHostDelegate::DefaultDeviceScaleFactor() {
+  return 1.0;
+}
+
 bool RenderWidgetHostDelegate::PreHandleKeyboardEvent(
     const NativeWebKeyboardEvent& event,
     bool* is_keyboard_shortcut) {
   return false;
 }
 
 bool RenderWidgetHostDelegate::HandleWheelEvent(
     const blink::WebMouseWheelEvent& event) {
   return false;
 }
@@ skipping 39 matching lines @@
 blink::WebDisplayMode RenderWidgetHostDelegate::GetDisplayMode(
     RenderWidgetHostImpl* render_widget_host) const {
   return blink::WebDisplayModeBrowser;
 }
 
 TextInputManager* RenderWidgetHostDelegate::GetTextInputManager() {
   return nullptr;
 }
 
 }  // namespace content