gpu: Early return GpuCommandBufferStub::OnWaitSyncPoint() if the sync point is retired.

If the sync point is retired, the scheduler already executed all gl calls before
the sync point, so OnWaitSyncPoint() does not need to do anything. Currently,
OnWaitSyncPoint() always sets the scheduler off and then on. This CL makes
OnWaitSyncPoint() be able to return early.

BUG=332401

Review URL: https://codereview.chromium.org/128123002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243932 0039d316-1c4b-4281-b951-d872f2087c98

content/common/gpu/gpu_command_buffer_stub.cc

@@ -768,13 +768,16 @@ void GpuCommandBufferStub::OnRetireSyncPoint(uint32 sync_point) {
 }
 
 bool GpuCommandBufferStub::OnWaitSyncPoint(uint32 sync_point) {
+  GpuChannelManager* manager = channel_->gpu_channel_manager();
+  if (manager->sync_point_manager()->IsSyncPointRetired(sync_point))
+    return true;
+
   if (sync_point_wait_count_ == 0) {
     TRACE_EVENT_ASYNC_BEGIN1("gpu", "WaitSyncPoint", this,
                              "GpuCommandBufferStub", this);
   }
   scheduler_->SetScheduled(false);
   ++sync_point_wait_count_;
-  GpuChannelManager* manager = channel_->gpu_channel_manager();
   manager->sync_point_manager()->AddSyncPointCallback(
       sync_point,
       base::Bind(&GpuCommandBufferStub::OnSyncPointRetired,

content/common/gpu/sync_point_manager.cc

@@ -57,4 +57,13 @@ void SyncPointManager::AddSyncPointCallback(uint32 sync_point,
   callback.Run();
 }
 
+bool SyncPointManager::IsSyncPointRetired(uint32 sync_point) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  {
+    base::AutoLock lock(lock_);
+    SyncPointMap::iterator it = sync_point_map_.find(sync_point);
+    return it == sync_point_map_.end();
+  }
+}
+
 }  // namespace content

content/common/gpu/sync_point_manager.h

@@ -35,6 +35,8 @@ class SyncPointManager : public base::RefCountedThreadSafe<SyncPointManager> {
   // called on the main thread.
   void AddSyncPointCallback(uint32 sync_point, const base::Closure& callback);
 
+  bool IsSyncPointRetired(uint32 sync_point);
+
  private:
   friend class base::RefCountedThreadSafe<SyncPointManager>;
   typedef std::vector<base::Closure> ClosureList;