ImageCapture: Implement takePhoto() for Mac AVFoundation

media/capture/video/mac/video_capture_device_mac.h

 // Copyright (c) 2012 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.
 
 // MacOSX implementation of generic VideoCaptureDevice, using AVFoundation as
 // native capture API. AVFoundation is available in versions 10.7 (Lion) and
 // later.
 
 #ifndef MEDIA_CAPTURE_VIDEO_MAC_VIDEO_CAPTURE_DEVICE_MAC_H_
 #define MEDIA_CAPTURE_VIDEO_MAC_VIDEO_CAPTURE_DEVICE_MAC_H_
@@ skipping 44 matching lines @@
 class VideoCaptureDeviceMac : public VideoCaptureDevice {
  public:
   explicit VideoCaptureDeviceMac(const Name& device_name);
   ~VideoCaptureDeviceMac() override;
 
   // VideoCaptureDevice implementation.
   void AllocateAndStart(
       const VideoCaptureParams& params,
       std::unique_ptr<VideoCaptureDevice::Client> client) override;
   void StopAndDeAllocate() override;
+  void TakePhoto(TakePhotoCallback callback) override;
 
   bool Init(VideoCaptureDevice::Name::CaptureApiType capture_api_type);
 
-  // Called to deliver captured video frames.
+  // Called to deliver captured video frames.  It's safe to call this method
+  // from any thread, including those controlled by AVFoundation.
   void ReceiveFrame(const uint8_t* video_frame,
                     int video_frame_length,
                     const VideoCaptureFormat& frame_format,
                     int aspect_numerator,
                     int aspect_denominator,
                     base::TimeDelta timestamp);
 
+  // Callbacks with the result of a still image capture, or in case of error,
+  // respectively. It's safe to call these methods from any thread.
+  void OnPhotoTaken(const uint8_t* image_data,
+                    size_t image_length,
+                    const std::string& mime_type);
+  void OnPhotoError();
+
   // Forwarder to VideoCaptureDevice::Client::OnError().
   void ReceiveError(const tracked_objects::Location& from_here,
                     const std::string& reason);
 
   // Forwarder to VideoCaptureDevice::Client::OnLog().
   void LogMessage(const std::string& message);
 
  private:
   void SetErrorState(const tracked_objects::Location& from_here,
                      const std::string& reason);
   bool UpdateCaptureResolution();
 
   // Flag indicating the internal state.
   enum InternalState { kNotInitialized, kIdle, kCapturing, kError };
 
   Name device_name_;
   std::unique_ptr<VideoCaptureDevice::Client> client_;
 
   VideoCaptureFormat capture_format_;
 
   // Only read and write state_ from inside this loop.
   const scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   InternalState state_;
 
   base::scoped_nsobject<VideoCaptureDeviceAVFoundation> capture_device_;
 
+  // To hold on to the TakePhotoCallback while the picture is being taken.
+  std::unique_ptr<TakePhotoCallback> photo_callback_;
+
   // Used with Bind and PostTask to ensure that methods aren't called after the
   // VideoCaptureDeviceMac is destroyed.
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<VideoCaptureDeviceMac> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureDeviceMac);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_CAPTURE_VIDEO_MAC_VIDEO_CAPTURE_DEVICE_MAC_H_