toggle FPS counter in compositor

cc/layer_tree_host.cc

Index: cc/layer_tree_host.cc
diff --git a/cc/layer_tree_host.cc b/cc/layer_tree_host.cc
index a15713666c6f423c2103ca1cb098426c87a31e58..8729fee84c89506eb49799211d340fe6801ae593 100644
--- a/cc/layer_tree_host.cc
+++ b/cc/layer_tree_host.cc
@@ -110,6 +110,7 @@ CCLayerTreeHost::CCLayerTreeHost(CCLayerTreeHostClient* client, const CCLayerTre
     , m_backgroundColor(SK_ColorWHITE)
     , m_hasTransparentBackground(false)
     , m_partialTextureUpdateRequests(0)
+    , m_showFPSCounter(false)
 {
     ASSERT(CCProxy::isMainThread());
     numLayerTreeInstances++;
@@ -277,6 +278,12 @@ void CCLayerTreeHost::finishCommitOnImplThread(CCLayerTreeHostImpl* hostImpl)
     m_commitNumber++;
 }
 
+void CCLayerTreeHost::setShowFPSCounter(bool show)
+{
+    m_showFPSCounter = show;
+    m_proxy->setShowFPSCounter(show);
+}
+
 void CCLayerTreeHost::setFontAtlas(scoped_ptr<CCFontAtlas> fontAtlas)
 {
     m_fontAtlas = fontAtlas.Pass();
@@ -286,7 +293,7 @@ void CCLayerTreeHost::setFontAtlas(scoped_ptr<CCFontAtlas> fontAtlas)
 void CCLayerTreeHost::willCommit()
 {
     m_client->willCommit();
-    if (m_rootLayer && m_settings.showDebugInfo()) {
+    if (m_rootLayer && (m_settings.showDebugInfo() || m_showFPSCounter)) {
         if (!m_hudLayer)
             m_hudLayer = HeadsUpDisplayLayerChromium::create();