Update the Chromium version of webrtc::VideoCaptureModule to be reference counted.

The reason is to be able to share ownership between PeerConnection and Chromium.

TEST=
BUG=
Review URL: http://codereview.chromium.org/7887002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@102286 0039d316-1c4b-4281-b951-d872f2087c98

content/renderer/media/video_capture_module_impl.cc

@@ -4,6 +4,7 @@
 
 #include "content/renderer/media/video_capture_module_impl.h"
 
+#include "base/atomicops.h"
 #include "content/renderer/media/video_capture_impl_manager.h"
 
 VideoCaptureModuleImpl::VideoCaptureModuleImpl(
@@ -20,7 +21,8 @@ VideoCaptureModuleImpl::VideoCaptureModuleImpl(
       frame_rate_(-1),
       video_type_(webrtc::kVideoI420),
       capture_engine_(NULL),
-      pending_start_(false) {
+      pending_start_(false),
+      ref_count_(0) {
   DCHECK(vc_manager_);
   Init();
 }
@@ -36,6 +38,21 @@ void VideoCaptureModuleImpl::Init() {
   capture_engine_ = vc_manager_->AddDevice(session_id_, this);
 }
 
+int32_t VideoCaptureModuleImpl::AddRef() {
+  VLOG(1) << "VideoCaptureModuleImpl::AddRef()";
+  return base::subtle::Barrier_AtomicIncrement(&ref_count_, 1);
+}
+
+int32_t VideoCaptureModuleImpl::Release() {
+  VLOG(1) << "VideoCaptureModuleImpl::Release()";
+  int ret = base::subtle::Barrier_AtomicIncrement(&ref_count_, -1);
+  if (ret == 0) {
+    VLOG(1) << "Reference count is zero, hence this object is now deleted.";
+    delete this;
+  }
+  return ret;
+}
+
 WebRtc_Word32 VideoCaptureModuleImpl::StartCapture(
     const webrtc::VideoCaptureCapability& capability) {
   message_loop_proxy_->PostTask(

content/renderer/media/video_capture_module_impl.h

@@ -22,7 +22,10 @@ class VideoCaptureModuleImpl
  public:
   VideoCaptureModuleImpl(const media::VideoCaptureSessionId id,
                          VideoCaptureImplManager* vc_manager);
-  virtual ~VideoCaptureModuleImpl();
+  // Implement reference counting. This make it possible to reference the
+  // object from both Chromium and WebRtc.
+  virtual int32_t AddRef() OVERRIDE;
+  virtual int32_t Release() OVERRIDE;
 
   // Override webrtc::videocapturemodule::VideoCaptureImpl implementation.
   virtual WebRtc_Word32 StartCapture(
@@ -45,6 +48,7 @@ class VideoCaptureModuleImpl
       const media::VideoCaptureParams& device_info);
 
  private:
+  virtual ~VideoCaptureModuleImpl();
   void Init();
 
   void StartCaptureOnCaptureThread(
@@ -76,6 +80,7 @@ class VideoCaptureModuleImpl
   media::VideoCapture* capture_engine_;
   bool pending_start_;
   webrtc::VideoCaptureCapability pending_cap_;
+  int ref_count_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureModuleImpl);
 };