Implement pointer lock across outer/inner WebContents.

content/browser/renderer_host/render_widget_host_delegate.h

Index: content/browser/renderer_host/render_widget_host_delegate.h
diff --git a/content/browser/renderer_host/render_widget_host_delegate.h b/content/browser/renderer_host/render_widget_host_delegate.h
index 6834658083ed9aa977353489e2dc3e70dee092f2..8030e158e9a2088c27d38d17d26825a5f2e6ac52 100644
--- a/content/browser/renderer_host/render_widget_host_delegate.h
+++ b/content/browser/renderer_host/render_widget_host_delegate.h
@@ -40,6 +40,7 @@ class RenderWidgetHostImpl;
 class RenderWidgetHostInputEventRouter;
 class RenderViewHostDelegateView;
 class TextInputManager;
+class WebContents;
 struct ScreenInfo;
 struct NativeWebKeyboardEvent;
 
@@ -249,6 +250,10 @@ class CONTENT_EXPORT RenderWidgetHostDelegate {
   // element accepts text input.
   virtual void FocusedNodeTouched(bool editable) {}
 
+  // Return this object cast to a WebContents, if it is one. If the object is
+  // not a WebContents, returns nullptr.
+  virtual WebContents* GetAsWebContents();
+
  protected:
   virtual ~RenderWidgetHostDelegate() {}
 };