Move local root/main frame methods from WebLocalFrame to WebFrameWidget

Add helpers to RenderFrameImpl and WebWidgetTestProxy to get to the
WebFrameWidget, because it's a big pain to go through WebFrame, to
its local root, to the WebFrameWidget.

[email protected]

Bug: 866140
Change-Id: I818e1f88512fb4a951059106079fd13feccd6271
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2210676
Commit-Queue: danakj <[email protected]>
Reviewed-by: Bo <[email protected]>
Reviewed-by: Istiaque Ahmed <[email protected]>
Reviewed-by: Daniel Cheng <[email protected]>
Cr-Commit-Position: refs/heads/master@{#771097}
diff --git a/content/renderer/render_frame_impl.h b/content/renderer/render_frame_impl.h
index 8233a8d..e9121dc 100644
--- a/content/renderer/render_frame_impl.h
+++ b/content/renderer/render_frame_impl.h
@@ -309,6 +309,9 @@
 
   // Returns the RenderWidget associated with this frame.
   RenderWidget* GetLocalRootRenderWidget();
+  // Returns the blink::WebFrameWidget attached to the RenderWidget that is
+  // associated with this frame.
+  blink::WebFrameWidget* GetLocalRootWebFrameWidget();
 
   // This method must be called after the WebLocalFrame backing this RenderFrame
   // has been created and added to the frame tree. It creates all objects that