Move LayerTreeHostImpl::SetVisible trace to "cc" from "webkit".

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 53eb58bb0c4a19007d295abd92a9db09fcff7201..40afab23051db07a5720e9ec2446c64cf77f3f8c 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -119,15 +119,12 @@ class ViewportAnchor {
 
 void DidVisibilityChange(LayerTreeHostImpl* id, bool visible) {
   if (visible) {
-    TRACE_EVENT_ASYNC_BEGIN1("webkit",
-                             "LayerTreeHostImpl::SetVisible",
-                             id,
-                             "LayerTreeHostImpl",
-                             id);
+    TRACE_EVENT_ASYNC_BEGIN1("cc", "LayerTreeHostImpl::SetVisible", id,
+                             "LayerTreeHostImpl", id);
     return;
   }
 
-  TRACE_EVENT_ASYNC_END0("webkit", "LayerTreeHostImpl::SetVisible", id);
+  TRACE_EVENT_ASYNC_END0("cc", "LayerTreeHostImpl::SetVisible", id);
 }
 
 size_t GetMaxTransferBufferUsageBytes(