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

content/browser/web_contents/web_contents_view_child_frame.cc

 // Copyright (c) 2016 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/web_contents/web_contents_view_child_frame.h"
 
 #include "build/build_config.h"
 #include "content/browser/frame_host/render_widget_host_view_child_frame.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/web_contents_view_delegate.h"
@@ skipping 29 matching lines @@
 }
 
 gfx::NativeView WebContentsViewChildFrame::GetContentNativeView() const {
   return GetOuterView()->GetContentNativeView();
 }
 
 gfx::NativeWindow WebContentsViewChildFrame::GetTopLevelNativeWindow() const {
   return GetOuterView()->GetTopLevelNativeWindow();
 }
 
+void WebContentsViewChildFrame::GetScreenInfo(
+    blink::WebScreenInfo* web_screen_info) const {
+  // TODO(wjmaclean): falling back to the default screen info is not what used
+  // to happen in RenderWidgetHostViewChildFrame, but it seems like the right
+  // thing to do. We should keep an eye on this in case the else-clause below
+  // causes problems.
+  if (web_contents_->GetOuterWebContents())
+    GetOuterView()->GetScreenInfo(web_screen_info);
+  else
+    WebContentsView::GetDefaultScreenInfo(web_screen_info);
+}
+
 void WebContentsViewChildFrame::GetContainerBounds(gfx::Rect* out) const {
   RenderWidgetHostView* view = web_contents_->GetRenderWidgetHostView();
   if (view)
     *out = view->GetViewBounds();
   else
     *out = gfx::Rect();
 }
 
 void WebContentsViewChildFrame::SizeContents(const gfx::Size& size) {
   // The RenderWidgetHostViewChildFrame is responsible for sizing the contents.
@@ skipping 94 matching lines @@
 void WebContentsViewChildFrame::StartDragging(
     const DropData& drop_data,
     WebDragOperationsMask ops,
     const gfx::ImageSkia& image,
     const gfx::Vector2d& image_offset,
     const DragEventSourceInfo& event_info) {
   NOTREACHED();
 }
 
 }  // namespace content