Revert of Replaced cc::SurfaceId::nonce_ with base::UnguessableToken

cc/surfaces/surface_manager.cc

 // 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.
 
 #include "cc/surfaces/surface_manager.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
 
 #include "base/logging.h"
 #include "cc/surfaces/surface.h"
 #include "cc/surfaces/surface_factory_client.h"
 #include "cc/surfaces/surface_id_allocator.h"
 
 namespace cc {
 
-const SurfaceId SurfaceManager::kRootSurfaceId(
-    FrameSinkId(0u, 0u),
-    LocalFrameId(0u, base::UnguessableToken::Create()));
+const SurfaceId SurfaceManager::kRootSurfaceId(FrameSinkId(0u, 0u),
+                                               LocalFrameId(0u, 0u));
 
 SurfaceManager::FrameSinkSourceMapping::FrameSinkSourceMapping()
     : client(nullptr), source(nullptr) {}
 
 SurfaceManager::FrameSinkSourceMapping::FrameSinkSourceMapping(
     const FrameSinkSourceMapping& other) = default;
 
 SurfaceManager::FrameSinkSourceMapping::~FrameSinkSourceMapping() {
   DCHECK(is_empty()) << "client: " << client
                      << ", children: " << children.size();
@@ skipping 408 matching lines @@
 
 void SurfaceManager::SurfaceCreated(const SurfaceId& surface_id,
                                     const gfx::Size& frame_size,
                                     float device_scale_factor) {
   CHECK(thread_checker_.CalledOnValidThread());
   for (auto& observer : observer_list_)
     observer.OnSurfaceCreated(surface_id, frame_size, device_scale_factor);
 }
 
 }  // namespace cc