Tiling priorities in Android Webview.

android_webview/browser/browser_view_renderer.h

Index: android_webview/browser/browser_view_renderer.h
diff --git a/android_webview/browser/browser_view_renderer.h b/android_webview/browser/browser_view_renderer.h
index 338b31d73e40698f4f36fd9533f78f141b3f7f6f..5d3ecc4e2bca61021c2e41013efe3a392609092c 100644
--- a/android_webview/browser/browser_view_renderer.h
+++ b/android_webview/browser/browser_view_renderer.h
@@ -7,6 +7,7 @@
 
 #include "android_webview/browser/global_tile_manager.h"
 #include "android_webview/browser/global_tile_manager_client.h"
+#include "android_webview/browser/parent_compositor_draw_constraints.h"
 #include "android_webview/browser/shared_renderer_state.h"
 #include "base/android/scoped_java_ref.h"
 #include "base/callback.h"
@@ -140,12 +141,17 @@ class BrowserViewRenderer : public content::SynchronousCompositorClient,
   virtual void SetNumTiles(size_t num_tiles,
                            bool effective_immediately) OVERRIDE;
 
- private:
-  void SetTotalRootLayerScrollOffset(gfx::Vector2dF new_value_dip);
   // Checks the continuous invalidate and block invalidate state, and schedule
   // invalidates appropriately. If |force_invalidate| is true, then send a view
   // invalidate regardless of compositor expectation.
   void EnsureContinuousInvalidation(bool force_invalidate);
+
+  // Post an invalidate if the parent draw constraints are stale and there is
+  // no pending invalidate.
+  void InvalidateOnceIfNeeded();
+
+ private:
+  void SetTotalRootLayerScrollOffset(gfx::Vector2dF new_value_dip);
   bool OnDrawSoftware(jobject java_canvas);
   bool CompositeSW(SkCanvas* canvas);
   void DidComposite();
@@ -199,6 +205,10 @@ class BrowserViewRenderer : public content::SynchronousCompositorClient,
   gfx::Vector2d last_on_draw_scroll_offset_;
   gfx::Rect last_on_draw_global_visible_rect_;
 
+  // The draw constraints from the parent compositor. These are only used for
+  // tiling priority.
+  ParentCompositorDrawConstraints parent_draw_constraints_;
+
   // When true, we should continuously invalidate and keep drawing, for example
   // to drive animation. This value is set by the compositor and should always
   // reflect the expectation of the compositor and not be reused for other