cc: split UpdateGpuRasterizationStatus() into two parts.

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 0bf40594b49d519a242d450b1859190577331892..ddd48770539fe21ca2e3bd07ca91b0e28ba61ab8 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -195,6 +195,7 @@ LayerTreeHostImpl::LayerTreeHostImpl(
       use_gpu_rasterization_(false),
       use_msaa_(false),
       gpu_rasterization_status_(GpuRasterizationStatus::OFF_DEVICE),
+      tree_resources_for_gpu_rasterization_dirty_(false),
       input_handler_client_(NULL),
       did_lock_scrolling_layer_(false),
       should_bubble_scrolls_(false),
@@ -308,7 +309,7 @@ void LayerTreeHostImpl::BeginCommit() {
 void LayerTreeHostImpl::CommitComplete() {
   TRACE_EVENT0("cc", "LayerTreeHostImpl::CommitComplete");
 
-  UpdateGpuRasterizationStatus();
+  UpdateTreeResourcesForGpuRasterizationIfNeeded();

[danakj, 2015/05/13 20:21:57]

can you comment that LTH sets stuff and this is acting on it?

[Stephen White, 2015/05/13 20:38:35]

Done.

   sync_tree()->set_needs_update_draw_properties();
 
   if (settings_.impl_side_painting) {
@@ -1621,6 +1622,14 @@ void LayerTreeHostImpl::UpdateGpuRasterizationStatus() {
   use_gpu_rasterization_ = use_gpu;
   use_msaa_ = use_msaa;
 
+  tree_resources_for_gpu_rasterization_dirty_ = true;
+}
+
+void LayerTreeHostImpl::UpdateTreeResourcesForGpuRasterizationIfNeeded() {
+  if (!tree_resources_for_gpu_rasterization_dirty_) {

[danakj, 2015/05/13 20:21:57]

nit: no {}

[Stephen White, 2015/05/13 20:38:35]

Done.

+    return;
+  }
+
   // Clean up and replace existing tile manager with another one that uses
   // appropriate rasterizer.
   ReleaseTreeResources();
@@ -1634,6 +1643,8 @@ void LayerTreeHostImpl::UpdateGpuRasterizationStatus() {
   // We would not have any content to draw until the pending tree is activated.
   // Prevent the active tree from drawing until activation.
   SetRequiresHighResToDraw();
+
+  tree_resources_for_gpu_rasterization_dirty_ = false;
 }
 
 const RendererCapabilitiesImpl&
@@ -1990,8 +2001,6 @@ void LayerTreeHostImpl::CreateAndSetRenderer() {
   }
   DCHECK(renderer_);
 
-  // Since the new renderer may be capable of MSAA, update status here.
-  UpdateGpuRasterizationStatus();
   renderer_->SetVisible(visible_);
   SetFullRootLayerDamage();
 
@@ -2176,6 +2185,9 @@ bool LayerTreeHostImpl::InitializeRenderer(
 
   CreateAndSetRenderer();
 
+  // Since the new renderer may be capable of MSAA, update status here.
+  UpdateGpuRasterizationStatus();
+
   if (settings_.impl_side_painting && settings_.raster_enabled)
     CreateAndSetTileManager();
   RecreateTreeResources();