FrameSinkIds use to WindowIds in window server, Process ID/Route ID in renderer

content/browser/frame_host/render_widget_host_view_child_frame.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 "content/browser/frame_host/render_widget_host_view_child_frame.h"
 
 #include <algorithm>
 #include <utility>
 #include <vector>
 
@@ skipping 24 matching lines @@
 #include "gpu/ipc/common/gpu_messages.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/geometry/size_f.h"
 
 namespace content {
 
 RenderWidgetHostViewChildFrame::RenderWidgetHostViewChildFrame(
     RenderWidgetHost* widget_host)
     : host_(RenderWidgetHostImpl::From(widget_host)),
-      frame_sink_id_(AllocateFrameSinkId()),
+      frame_sink_id_(
+          base::checked_cast<uint32_t>(widget_host->GetProcess()->GetID()),
+          base::checked_cast<uint32_t>(widget_host->GetRoutingID())),
       next_surface_sequence_(1u),
       last_compositor_frame_sink_id_(0),
       current_surface_scale_factor_(1.f),
       ack_pending_count_(0),
       frame_connector_(nullptr),
       begin_frame_source_(nullptr),
       weak_factory_(this) {
   id_allocator_.reset(new cc::SurfaceIdAllocator(frame_sink_id_));
   GetSurfaceManager()->RegisterFrameSinkId(frame_sink_id_);
   RegisterFrameSinkId();
@@ skipping 657 matching lines @@
 
 bool RenderWidgetHostViewChildFrame::IsChildFrameForTesting() const {
   return true;
 }
 
 cc::SurfaceId RenderWidgetHostViewChildFrame::SurfaceIdForTesting() const {
   return surface_id_;
 };
 
 }  // namespace content