Split ThreadProxy methods to ProxyMain and ProxyImpl.

cc/base/completion_event.h

Index: cc/base/completion_event.h
diff --git a/cc/base/completion_event.h b/cc/base/completion_event.h
index 6bae765dd20e2173065bccab670afd2618547a95..36e8954c99565f35b70847b1cc3b85cdbc1b8667 100644
--- a/cc/base/completion_event.h
+++ b/cc/base/completion_event.h
@@ -8,6 +8,7 @@
 #include "base/logging.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread_restrictions.h"
+#include "base/time/time.h"
 
 namespace cc {
 
@@ -41,6 +42,16 @@ class CompletionEvent {
     event_.Wait();
   }
 
+  void TimedWait(const base::TimeDelta& max_time) {
+#if DCHECK_IS_ON()
+    DCHECK(!waited_);
+    waited_ = true;
+#endif
+    event_.TimedWait(max_time);
+  }
+
+  bool IsSignaled() { return event_.IsSignaled(); }
+
   void Signal() {
 #if DCHECK_IS_ON()
     DCHECK(!signaled_);