cc: Fix recording of GPU rasterization histogram for renderer compositor.

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index 6eb60f64390c425fec8fd98fad4578c69f8b21cf..b4a480cb78b956ec98c3845ff333eec9e58fbad8 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -737,8 +737,8 @@ static Layer* FindFirstScrollableLayer(Layer* layer) {
 
 void LayerTreeHost::RecordGpuRasterizationHistogram() {
   // Gpu rasterization is only supported for Renderer compositors.
-  // Checking for IsThreaded() to exclude Browser compositors.
-  if (gpu_rasterization_histogram_recorded_ || IsThreaded())
+  // Checking for IsSingleThreaded() to exclude Browser compositors.
+  if (gpu_rasterization_histogram_recorded_ || IsSingleThreaded())

[vmpstr, 2015/12/10 00:35:00]

It would be nice to add a test so this doesn't regress. Is it possible to write
a test that checks that gpu_rasterization_histogram_recorded_ doesn't become
true if this is run in single threaded mode?

     return;
 
   // Record how widely gpu rasterization is enabled.