Add a |scope| argument to TRACE_EVENT_INSTANT* and require its presence.

cc/layer_tree_host_impl.cc

Index: cc/layer_tree_host_impl.cc
diff --git a/cc/layer_tree_host_impl.cc b/cc/layer_tree_host_impl.cc
index e17d3ce30a15fdfbd6119f1afff45c0e82e5cb4d..d517b7e6d09573f51da70b185ba70dcbfe520839 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -227,23 +227,28 @@ bool LayerTreeHostImpl::canDraw()
     // in the proper places and update the notifyIfCanDrawChanged test.
 
     if (!rootLayer()) {
-        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::canDraw no root layer");
+        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::canDraw no root layer",
+                             TRACE_EVENT_SCOPE_THREAD);
         return false;
     }
     if (deviceViewportSize().IsEmpty()) {
-        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::canDraw empty viewport");
+        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::canDraw empty viewport",
+                             TRACE_EVENT_SCOPE_THREAD);
         return false;
     }
     if (m_activeTree->ViewportSizeInvalid()) {
-        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::canDraw viewport size recently changed");
+        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::canDraw viewport size recently changed",
+                             TRACE_EVENT_SCOPE_THREAD);
         return false;
     }
     if (!m_renderer) {
-        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::canDraw no renderer");
+        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::canDraw no renderer",
+                             TRACE_EVENT_SCOPE_THREAD);
         return false;
     }
     if (m_activeTree->ContentsTexturesPurged()) {
-        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::canDraw contents textures purged");
+        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::canDraw contents textures purged",
+                             TRACE_EVENT_SCOPE_THREAD);
         return false;
     }
     return true;
@@ -817,7 +822,7 @@ void LayerTreeHostImpl::drawLayers(FrameData& frame)
         m_debugRectHistory->saveDebugRectsForCurrentFrame(rootLayer(), *frame.renderSurfaceLayerList, frame.occludingScreenSpaceRects, frame.nonOccludingScreenSpaceRects, m_debugState);
 
     if (m_debugState.traceAllRenderedFrames) {
-        TRACE_EVENT_INSTANT1("cc.debug", "Frame",
+        TRACE_EVENT_INSTANT1("cc.debug", "Frame", TRACE_EVENT_SCOPE_THREAD,
                              "frame", ValueToString(frameStateAsValue()));
     }