Centralize FrameSinkId allocation in one place

ui/compositor/test/in_process_context_factory.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 "ui/compositor/test/in_process_context_factory.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 111 matching lines @@
 
 struct InProcessContextFactory::PerCompositorData {
   gpu::SurfaceHandle surface_handle = gpu::kNullSurfaceHandle;
   std::unique_ptr<cc::BeginFrameSource> begin_frame_source;
   std::unique_ptr<cc::Display> display;
 };
 
 InProcessContextFactory::InProcessContextFactory(
     bool context_factory_for_test,
     cc::SurfaceManager* surface_manager)
-    : next_surface_sink_id_(1u),
+    : frame_sink_id_allocator_(
+          0 /* client_id, not to conflict with the client_id
+                                   generated from RenderWidgetHostImpl */),
       use_test_surface_(true),
       context_factory_for_test_(context_factory_for_test),
       surface_manager_(surface_manager) {
   DCHECK(surface_manager);
   DCHECK_NE(gl::GetGLImplementation(), gl::kGLImplementationNone)
       << "If running tests, ensure that main() is calling "
       << "gl::GLSurfaceTestSupport::InitializeOneOff()";
 }
 
 InProcessContextFactory::~InProcessContextFactory() {
@@ skipping 135 matching lines @@
 gpu::GpuMemoryBufferManager*
 InProcessContextFactory::GetGpuMemoryBufferManager() {
   return &gpu_memory_buffer_manager_;
 }
 
 cc::TaskGraphRunner* InProcessContextFactory::GetTaskGraphRunner() {
   return &task_graph_runner_;
 }
 
 cc::FrameSinkId InProcessContextFactory::AllocateFrameSinkId() {
-  // The FrameSinkId generated here must be unique with
-  // RenderWidgetHostViewAura's
-  // and RenderWidgetHostViewMac's FrameSinkId allocation.
-  // TODO(crbug.com/685777): Centralize allocation in one place for easier
-  // maintenance.
-  return cc::FrameSinkId(0, next_surface_sink_id_++);
+  return frame_sink_id_allocator_.NextFrameSinkId();
 }
 
 cc::SurfaceManager* InProcessContextFactory::GetSurfaceManager() {
   return surface_manager_;
 }
 
 void InProcessContextFactory::SetDisplayVisible(ui::Compositor* compositor,
                                                 bool visible) {
   if (!per_compositor_data_.count(compositor))
     return;
@@ skipping 32 matching lines @@
     data->surface_handle = tracker->AddSurfaceForNativeWidget(widget);
 #endif
   }
 
   PerCompositorData* return_ptr = data.get();
   per_compositor_data_[compositor] = std::move(data);
   return return_ptr;
 }
 
 }  // namespace ui