Expose the capturePicture feature in RenderView for Android WebView legacy API support.

content/renderer/render_widget.h

Index: content/renderer/render_widget.h
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index 725bdc50aa5cf351954c386187da3879fafc8791..1f35fb1cba06ec513cefd50deeb1d9dc0897faf0 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -190,6 +190,9 @@ class CONTENT_EXPORT RenderWidget
   // Close the underlying WebWidget.
   virtual void Close();
 
+  // Notifies about a compositor frame commit operation having finished.
+  virtual void DidCommitCompositorFrame();
+
   float filtered_time_per_frame() const {
     return filtered_time_per_frame_;
   }