Hook up ui::Compositor to Display's BeginFrameSource

cc/surfaces/surface_id.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_SURFACES_SURFACE_ID_H_
 #define CC_SURFACES_SURFACE_ID_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <functional>
 
 namespace cc {
 
 struct SurfaceId {
   SurfaceId() : id(0) {}
   explicit SurfaceId(uint64_t id) : id(id) {}
 
   bool is_null() const { return id == 0; }
 
+  // See SurfaceIdAllocator::GenerateId.
+  uint32_t id_namespace() const { return id >> 32; }
+
   uint64_t id;
 };
 
 inline bool operator==(const SurfaceId& a, const SurfaceId& b) {
   return a.id == b.id;
 }
 
 inline bool operator!=(const SurfaceId& a, const SurfaceId& b) {
   return !(a == b);
 }
 
 inline bool operator<(const SurfaceId& a, const SurfaceId& b) {
   return a.id < b.id;
 }
 
 struct SurfaceIdHash {
   size_t operator()(const SurfaceId& key) const {
     return std::hash<uint64_t>()(key.id);
   }
 };
 
 }  // namespace cc
 
 #endif  // CC_SURFACES_SURFACE_ID_H_