Tiling priorities in Android Webview.

android_webview/browser/hardware_renderer.cc

Index: android_webview/browser/hardware_renderer.cc
diff --git a/android_webview/browser/hardware_renderer.cc b/android_webview/browser/hardware_renderer.cc
index 4ed2859b1399038a5dd060058b0bfcd450158404..27bd9821befd6bee34ead6b23d241242fad13d4b 100644
--- a/android_webview/browser/hardware_renderer.cc
+++ b/android_webview/browser/hardware_renderer.cc
@@ -207,6 +207,17 @@ void HardwareRenderer::DrawGL(bool stencil_enabled,
     layer_tree_host_->Composite(gfx::FrameTime::Now());
   }
   gl_surface_->ResetBackingFrameBufferObject();
+
+  // Need to post the new transform matrix back to child compositor
+  // because there is no onDraw during a Render Thread animation, and child
+  // compositor might not have the tiles rasterized as the animation goes on.
+  ParentCompositorDrawConstraints draw_constraints(
+      draw_info->is_layer, transform, gfx::Rect(viewport_));
+  if (draw_constraints_ != draw_constraints) {
+    draw_constraints_ = draw_constraints;
+    shared_renderer_state_->PostExternalDrawConstraintsToChildCompositor(
+        draw_constraints);
+  }
 }
 
 scoped_ptr<cc::OutputSurface> HardwareRenderer::CreateOutputSurface(