[Android WebView] Fallback tick

android_webview/browser/in_process_view_renderer.h

 // Copyright 2013 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_IN_PROCESS_IN_PROCESS_VIEW_RENDERER_H_
 #define ANDROID_WEBVIEW_BROWSER_IN_PROCESS_IN_PROCESS_VIEW_RENDERER_H_
 
 #include "android_webview/browser/browser_view_renderer.h"
 
+#include "base/cancelable_callback.h"
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/android/synchronous_compositor_client.h"
 #include "ui/gfx/vector2d_f.h"
 
 namespace content {
 class SynchronousCompositor;
 class WebContents;
 }
 
 typedef void* EGLContext;
@@ skipping 41 matching lines @@
   virtual void SetTotalRootLayerScrollOffset(
       gfx::Vector2dF new_value_css) OVERRIDE;
   virtual gfx::Vector2dF GetTotalRootLayerScrollOffset() OVERRIDE;
 
   void WebContentsGone();
 
  private:
   void EnsureContinuousInvalidation(AwDrawGLInfo* draw_info);
   bool DrawSWInternal(jobject java_canvas,
                       const gfx::Rect& clip_bounds);
-  bool RenderSW(SkCanvas* canvas);
   bool CompositeSW(SkCanvas* canvas);
 
+  // If we call up view invalidate and OnDraw is not called before a deadline,
+  // then we keep ticking the SynchronousCompositor so it can make progress.
+  void FallbackTickFired();
+
   BrowserViewRenderer::Client* client_;
   BrowserViewRenderer::JavaHelper* java_helper_;
   content::WebContents* web_contents_;
   content::SynchronousCompositor* compositor_;
 
   bool visible_;
   float dip_scale_;
 
   // When true, we should continuously invalidate and keep drawing, for example
   // to drive animation.
   bool continuous_invalidate_;
   // Used to block additional invalidates while one is already pending or before
   // compositor draw which may switch continuous_invalidate on and off in the
   // process.
   bool block_invalidates_;
+  // Holds a callback to FallbackTickFired while it is pending.
+  base::CancelableClosure fallback_tick_;
 
   int width_;
   int height_;
 
   bool attached_to_window_;
   bool hardware_initialized_;
   bool hardware_failed_;
 
   // Used only for detecting Android View System context changes.
   // Not to be used between draw calls.
   EGLContext last_egl_context_;
 
   // Last View scroll when View.onDraw() was called.
   gfx::Vector2d scroll_at_start_of_frame_;
 
   // Current scroll offset in CSS pixels.
   gfx::Vector2dF scroll_offset_css_;
 
   DISALLOW_COPY_AND_ASSIGN(InProcessViewRenderer);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_IN_PROCESS_IN_PROCESS_VIEW_RENDERER_H_