Revert of Remove fallback tick software draw.

android_webview/browser/browser_view_renderer.h

 // Copyright (c) 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_BROWSER_VIEW_RENDERER_H_
 #define ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_H_
 
 #include "android_webview/browser/parent_compositor_draw_constraints.h"
 #include "android_webview/browser/shared_renderer_state.h"
 #include "base/callback.h"
@@ skipping 102 matching lines @@
   void DidOverscroll(const gfx::Vector2dF& accumulated_overscroll,
                      const gfx::Vector2dF& latest_overscroll_delta,
                      const gfx::Vector2dF& current_fling_velocity) override;
 
   void UpdateParentDrawConstraints();
   void DetachFunctorFromView();
 
  private:
   void SetTotalRootLayerScrollOffset(const gfx::Vector2dF& new_value_dip);
   bool CanOnDraw();
+  // Posts an invalidate with fallback tick. All invalidates posted while an
+  // invalidate is pending will be posted as a single invalidate after the
+  // pending invalidate is done.
+  void PostInvalidateWithFallback();
+  void CancelFallbackTick();
   void UpdateCompositorIsActive();
   bool CompositeSW(SkCanvas* canvas);
   scoped_refptr<base::trace_event::ConvertableToTraceFormat>
   RootLayerStateAsValue(const gfx::Vector2dF& total_scroll_offset_dip,
                         const gfx::SizeF& scrollable_size_dip);
 
+  bool CompositeHw();
   void ReturnUnusedResource(scoped_ptr<ChildFrame> frame);
   void ReturnResourceFromParent();
 
   // 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.
   // Do this in a two stage tick due to native MessageLoop favors delayed task,
   // so ensure delayed task is inserted only after the draw task returns.
   void PostFallbackTick();
   void FallbackTickFired();
 
+  // Force invoke the compositor to run produce a 1x1 software frame that is
+  // immediately discarded. This is a hack to force invoke parts of the
+  // compositor that are not directly exposed here.
+  void ForceFakeCompositeSW();
+
   gfx::Vector2d max_scroll_offset() const;
 
   void UpdateMemoryPolicy();
 
   // For debug tracing or logging. Return the string representation of this
   // view renderer's state.
   std::string ToString() const;
 
   BrowserViewRendererClient* client_;
   SharedRendererState shared_renderer_state_;
@@ skipping 12 matching lines @@
   float min_page_scale_factor_;
   float max_page_scale_factor_;
   bool on_new_picture_enable_;
   bool clear_view_;
 
   bool offscreen_pre_raster_;
 
   gfx::Vector2d last_on_draw_scroll_offset_;
   gfx::Rect last_on_draw_global_visible_rect_;
 
+  base::CancelableClosure post_fallback_tick_;
+  base::CancelableClosure fallback_tick_fired_;
+  bool fallback_tick_pending_;
+
   gfx::Size size_;
 
   gfx::SizeF scrollable_size_dip_;
 
   // Current scroll offset in CSS pixels.
   // TODO(miletus): Make scroll_offset_dip_ a gfx::ScrollOffset.
   gfx::Vector2dF scroll_offset_dip_;
 
   // Max scroll offset in CSS pixels.
   // TODO(miletus): Make max_scroll_offset_dip_ a gfx::ScrollOffset.
   gfx::Vector2dF max_scroll_offset_dip_;
 
   // Used to prevent rounding errors from accumulating enough to generate
   // visible skew (especially noticeable when scrolling up and down in the same
   // spot over a period of time).
   // TODO(miletus): Make overscroll_rounding_error_ a gfx::ScrollOffset.
   gfx::Vector2dF overscroll_rounding_error_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserViewRenderer);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_BROWSER_VIEW_RENDERER_H_