cc: Without valid frame, delegated renderer layer is not drawable

cc/delegated_renderer_layer_impl.cc

Index: cc/delegated_renderer_layer_impl.cc
diff --git a/cc/delegated_renderer_layer_impl.cc b/cc/delegated_renderer_layer_impl.cc
index a8cdd549d1fbbe70d8165d28aa903c8e479606e9..588ede0b41c32520b9090ba5f6715404dd04a3da 100644
--- a/cc/delegated_renderer_layer_impl.cc
+++ b/cc/delegated_renderer_layer_impl.cc
@@ -46,23 +46,14 @@ void DelegatedRendererLayerImpl::SetFrameData(
   // will be in layer space.
   RenderPass* new_root_pass = frame_data->render_pass_list.empty() ?
                               NULL : frame_data->render_pass_list.back();
-  bool new_frame_is_empty = !new_root_pass;
 
-  RenderPass* old_root_pass = render_passes_in_draw_order_.empty() ?
-                              NULL : render_passes_in_draw_order_.back();
-  bool old_frame_is_empty = !old_root_pass;
-
-  gfx::RectF damage_in_layer;
-  if (new_frame_is_empty) {
-    if (!old_frame_is_empty)
-      damage_in_layer = gfx::Rect(bounds());
-  } else {
+  if (new_root_pass) {

[piman, 2013/02/27 21:04:35]

pushing even slightly further, you can save an if by testing
!frame_data->render_pass_list.empty() here and only fetching
frame_data->render_pass_list.back() inside the if.

[danakj, 2013/02/27 21:05:27]

True! Let's see how the remap CL looks, I can do that there.

[danakj, 2013/02/27 21:40:45]

Oh right, this is waiting on CQ from another CL anyways. Done!

     DCHECK(!new_root_pass->output_rect.IsEmpty());
-    damage_in_layer = MathUtil::mapClippedRect(
+    gfx::RectF damage_in_layer = MathUtil::mapClippedRect(
         DelegatedFrameToLayerSpaceTransform(new_root_pass->output_rect.size()),
         damage_in_frame);
+    setUpdateRect(gfx::UnionRects(updateRect(), damage_in_layer));
   }
-  setUpdateRect(gfx::UnionRects(updateRect(), damage_in_layer));
 
   // TODO(danakj): Convert the resource ids the render passes and return data
   // for a frame ack.