Explicitly specify the ui::Compositor to DelegatedFrameHost

ui/compositor/compositor.cc

Index: ui/compositor/compositor.cc
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index 0e917265415fd26e79e453e48160b41050ca6031..3def4a6a22a7cd025ac6b4b8aa0d8ec2af481b63 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -299,25 +299,15 @@ scoped_refptr<CompositorVSyncManager> Compositor::vsync_manager() const {
 }
 
 void Compositor::AddObserver(CompositorObserver* observer) {
-#if defined(OS_MACOSX)
-  // Debugging instrumentation for crbug.com/401630.
-  // TODO(ccameron): remove this.
-  CHECK(observer);
+  DCHECK(observer);
   if (!observer_list_.HasObserver(observer))
     observer->observing_count_ += 1;
-#endif
-
   observer_list_.AddObserver(observer);
 }
 
 void Compositor::RemoveObserver(CompositorObserver* observer) {
-#if defined(OS_MACOSX)
-  // Debugging instrumentation for crbug.com/401630.
-  // TODO(ccameron): remove this.
   if (observer_list_.HasObserver(observer))
     observer->observing_count_ -= 1;
-#endif
-
   observer_list_.RemoveObserver(observer);
 }