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 511969e34f0c029d7d4a0256d319e6e2023e4bc9..acd677221d7ca6221d7171c01fd674ea3b7b86de 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_.equals(draw_constraints)) {

[boliu, 2014/07/29 19:02:41]

Remember we are not looking for "equals" exactly. We don't care about the
surface size if we are not in a layer.

Let's move this block near the beginning of the method, let's say right after
checking context changed.

[hush (inactive), 2014/07/29 21:14:21]

Yeah.

Why do we want to move this to the beginning of the function? Just to reduce a
little bit of latency when you post it to UI?
Also for the record, this portion of the code will be in "DrawGL" after I rebase
past kModeSync CL: https://codereview.chromium.org/414163002/
On 2014/07/29 19:02:41, boliu wrote:

+    draw_constraints_ = draw_constraints;
+    shared_renderer_state_->PostExternalDrawConstraintsToChildCompositor(
+        draw_constraints);
+  }
 }
 
 scoped_ptr<cc::OutputSurface> HardwareRenderer::CreateOutputSurface(