Limit the number of ARC codec

chrome/gpu/arc_gpu_video_decode_accelerator.h

Index: chrome/gpu/arc_gpu_video_decode_accelerator.h
diff --git a/chrome/gpu/arc_gpu_video_decode_accelerator.h b/chrome/gpu/arc_gpu_video_decode_accelerator.h
index 5685f56e57136381ba1d81dd38b568a7b78f13d8..df1458d9dc53454bf71ba3ca0833c1e094f9e7a7 100644
--- a/chrome/gpu/arc_gpu_video_decode_accelerator.h
+++ b/chrome/gpu/arc_gpu_video_decode_accelerator.h
@@ -32,8 +32,9 @@ class ArcGpuVideoDecodeAccelerator
   ~ArcGpuVideoDecodeAccelerator() override;
 
   // Implementation of the ArcVideoAccelerator interface.
-  bool Initialize(const Config& config,
-                  ArcVideoAccelerator::Client* client) override;
+  ArcVideoAccelerator::Result Initialize(
+      const Config& config,
+      ArcVideoAccelerator::Client* client) override;
   void SetNumberOfOutputBuffers(size_t number) override;
   void BindSharedMemory(PortType port,
                         uint32_t index,
@@ -119,6 +120,12 @@ class ArcGpuVideoDecodeAccelerator
   // Returns |nullptr| if it cannot be found.
   InputRecord* FindInputRecord(int32_t bitstream_buffer_id);
 
+  // Global counter that keeps track the number of active clients (i.e., how
+  // many VDAs in use by this class).
+  // Since this class only works on the same thread, it's safe to access
+  // |client_count_| without lock.
+  static int client_count_;
+
   std::unique_ptr<media::VideoDecodeAccelerator> vda_;
 
   // It's safe to use the pointer here, the life cycle of the |arc_client_|