Limit the number of ARC codec

chrome/gpu/arc_gpu_video_decode_accelerator.h

 // Copyright 2016 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.
 
 #ifndef CHROME_GPU_ARC_GPU_VIDEO_DECODE_ACCELERATOR_H_
 #define CHROME_GPU_ARC_GPU_VIDEO_DECODE_ACCELERATOR_H_
 
 #include <list>
 #include <memory>
 #include <queue>
@@ skipping 14 matching lines @@
 // frames back to the ARC side.
 class ArcGpuVideoDecodeAccelerator
     : public ArcVideoAccelerator,
       public media::VideoDecodeAccelerator::Client,
       public base::SupportsWeakPtr<ArcGpuVideoDecodeAccelerator> {
  public:
   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,
                         base::ScopedFD ashmem_fd,
                         off_t offset,
                         size_t length) override;
   void BindDmabuf(PortType port,
                   uint32_t index,
                   base::ScopedFD dmabuf_fd,
                   int32_t stride) override;
@@ skipping 65 matching lines @@
   // |buffer_index| is the index of the associated input buffer. The |timestamp|
   // is the time the video frame should be displayed.
   void CreateInputRecord(int32_t bitstream_buffer_id,
                          uint32_t buffer_index,
                          int64_t timestamp);
 
   // Finds the InputRecord which matches to given |bitstream_buffer_id|.
   // 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_|
   // is longer than this ArcGpuVideoDecodeAccelerator.
   ArcVideoAccelerator::Client* arc_client_;
 
   // The next ID for the bitstream buffer, started from 0.
   int32_t next_bitstream_buffer_id_;
 
   gfx::Size coded_size_;
@@ skipping 16 matching lines @@
 
   gpu::GpuPreferences gpu_preferences_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcGpuVideoDecodeAccelerator);
 };
 
 }  // namespace arc
 }  // namespace chromeos
 
 #endif  // CHROME_GPU_ARC_GPU_VIDEO_DECODE_ACCELERATOR_H_