Centralize FrameSinkId allocation in one place

content/browser/compositor/gpu_process_transport_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 "content/browser/compositor/gpu_process_transport_factory.h"
 
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 157 matching lines @@
 struct GpuProcessTransportFactory::PerCompositorData {
   gpu::SurfaceHandle surface_handle = gpu::kNullSurfaceHandle;
   BrowserCompositorOutputSurface* display_output_surface = nullptr;
   std::unique_ptr<cc::SyntheticBeginFrameSource> begin_frame_source;
   ReflectorImpl* reflector = nullptr;
   std::unique_ptr<cc::Display> display;
   bool output_is_secure = false;
 };
 
 GpuProcessTransportFactory::GpuProcessTransportFactory()
-    : task_graph_runner_(new cc::SingleThreadTaskGraphRunner),
+    : frame_sink_id_allocator_(
+          0 /* client_id, not to conflict with the client_id

[boliu, 2017/02/15 23:58:56]

nit: 0u everwhere

[Fady Samuel, 2017/02/17 14:00:24]

nit: Maybe add a constexpr at the top of the file instead and put the comment
there. This comment looks a bit awkward inline here.

[xlai (Olivia), 2017/02/17 15:55:11]

Done.

[xlai (Olivia), 2017/02/17 15:55:11]

Done.

+                                   generated from RenderWidgetHostImpl */),
+      task_graph_runner_(new cc::SingleThreadTaskGraphRunner),
       callback_factory_(this) {
   cc::SetClientNameForMetrics("Browser");
 
   surface_manager_ = base::WrapUnique(new cc::SurfaceManager);
 
   task_graph_runner_->Start("CompositorTileWorker1",
                             base::SimpleThread::Options());
 #if defined(OS_WIN)
   software_backing_.reset(new OutputDeviceBacking);
 #endif
@@ skipping 493 matching lines @@
 ui::ContextFactory* GpuProcessTransportFactory::GetContextFactory() {
   return this;
 }
 
 ui::ContextFactoryPrivate*
 GpuProcessTransportFactory::GetContextFactoryPrivate() {
   return this;
 }
 
 cc::FrameSinkId GpuProcessTransportFactory::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_sink_id_++);
+  return frame_sink_id_allocator_.NextFrameSinkId();
 }
 
 void GpuProcessTransportFactory::SetDisplayVisible(ui::Compositor* compositor,
                                                    bool visible) {
   PerCompositorDataMap::iterator it = per_compositor_data_.find(compositor);
   if (it == per_compositor_data_.end())
     return;
   PerCompositorData* data = it->second.get();
   DCHECK(data);
   // The compositor will always SetVisible on the Display once it is set up, so
@@ skipping 206 matching lines @@
       shared_vulkan_context_provider_ =
           cc::VulkanInProcessContextProvider::Create();
     }
 
     shared_vulkan_context_provider_initialized_ = true;
   }
   return shared_vulkan_context_provider_;
 }
 
 }  // namespace content