Add synchronous requestDrawGL

android_webview/browser/browser_view_renderer_client.h

 // Copyright 2014 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.
 
 #ifndef ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_CLIENT_H_
 #define ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_CLIENT_H_
 
 #include "base/android/scoped_java_ref.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/size_f.h"
 #include "ui/gfx/geometry/vector2d_f.h"
 
 namespace android_webview {
 
 class BrowserViewRendererClient {
  public:
   // Request DrawGL be called. Passing null |canvas| implies the request
-  // will be of AwDrawGLInfo::kModeProcess type. The callback
-  // may never be made, and the mode may be promoted to kModeDraw.
-  virtual bool RequestDrawGL(jobject canvas) = 0;
+  // will be of AwDrawGLInfo::kModeProcess type. |wait_for_completion|
+  // will cause the call to block until DrawGL has happened; it does not
+  // work when |canvas| is not NULL. The callback may never be made, and
+  // the mode may be promoted to kModeDraw.
+  virtual bool RequestDrawGL(jobject canvas, bool wait_for_completion) = 0;
 
   // Called when a new Picture is available. Needs to be enabled
   // via the EnableOnNewPicture method.
   virtual void OnNewPicture() = 0;
 
   // Called to trigger view invalidations.
   virtual void PostInvalidate() = 0;
 
   // Called to get view's absolute location on the screen.
   virtual gfx::Point GetLocationOnScreen() = 0;
@@ skipping 19 matching lines @@
   // Handle overscroll.
   virtual void DidOverscroll(gfx::Vector2d overscroll_delta) = 0;
 
  protected:
   virtual ~BrowserViewRendererClient() {}
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_CLIENT_H_