Make VideoCaptureController single-threaded and not ref counted.

content/browser/renderer_host/media/video_capture_manager.h

Index: content/browser/renderer_host/media/video_capture_manager.h
diff --git a/content/browser/renderer_host/media/video_capture_manager.h b/content/browser/renderer_host/media/video_capture_manager.h
index fb0a574a3e7ff4a49e77a8262b1c2f110491428d..0e3d45b66c1a7ca64d02808e7bb1618a78e30d00 100644
--- a/content/browser/renderer_host/media/video_capture_manager.h
+++ b/content/browser/renderer_host/media/video_capture_manager.h
@@ -17,6 +17,7 @@
 #include <string>
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "base/process/process_handle.h"
 #include "content/browser/renderer_host/media/media_stream_provider.h"
 #include "content/browser/renderer_host/media/video_capture_controller_event_handler.h"
@@ -26,13 +27,16 @@
 #include "media/video/capture/video_capture_types.h"
 
 namespace content {
-class MockVideoCaptureManager;
 class VideoCaptureController;
 class VideoCaptureControllerEventHandler;
 
 // VideoCaptureManager opens/closes and start/stops video capture devices.
 class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
  public:
+  // Callback used to signal the completion of a controller lookup.
+  typedef base::Callback<
+      void(const base::WeakPtr<VideoCaptureController>&)> DoneCB;

[Ami GONE FROM CHROMIUM, 2013/09/14 00:32:24]

"DoneCB"?  Oh, so your "callback" signifies being "done"?
</youdontsay>

Not that I have a fantastic alternate suggestion :(

[ncarter (slow), 2013/09/14 01:29:31]

One must pick one's battles.

+
   // Calling |Start| of this id will open the first device, even though open has
   // not been called. This is used to be able to use video capture devices
   // before MediaStream is implemented in Chrome and WebKit.
@@ -69,12 +73,11 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
   // On success, the controller is returned via calling |done_cb|, indicating
   // that the client was successfully added. A NULL controller is passed to
   // the callback on failure.
-  void StartCaptureForClient(
-      const media::VideoCaptureParams& capture_params,
-      base::ProcessHandle client_render_process,
-      VideoCaptureControllerID client_id,
-      VideoCaptureControllerEventHandler* client_handler,
-      base::Callback<void(VideoCaptureController*)> done_cb);
+  void StartCaptureForClient(const media::VideoCaptureParams& capture_params,
+                             base::ProcessHandle client_render_process,
+                             VideoCaptureControllerID client_id,
+                             VideoCaptureControllerEventHandler* client_handler,
+                             DoneCB done_cb);

[Ami GONE FROM CHROMIUM, 2013/09/14 00:32:24]

Shouldn't callbacks be passed by const&?

[ncarter (slow), 2013/09/14 01:29:31]

Done.

 
   // Called by VideoCaptureHost to remove |client_handler|. If this is the last
   // client of the device, the |controller| and its VideoCaptureDevice may be
@@ -94,7 +97,7 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
       base::ProcessHandle client_render_process,
       VideoCaptureControllerID client_id,
       VideoCaptureControllerEventHandler* client_handler,
-      base::Callback<void(VideoCaptureController*)> done_cb,
+      DoneCB done_cb,
       const media::VideoCaptureDevice::Names& device_names);
 
   // Helper routine implementing StartCaptureForClient().
@@ -103,7 +106,7 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
       base::ProcessHandle client_render_process,
       VideoCaptureControllerID client_id,
       VideoCaptureControllerEventHandler* client_handler,
-      base::Callback<void(VideoCaptureController*)> done_cb);
+      DoneCB done_cb);
 
   // Check to see if |entry| has no clients left on its controller. If so,
   // remove it from the list of devices, and delete it asynchronously. |entry|
@@ -135,22 +138,17 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
       MediaStreamType stream_type);
 
   // Create and Start a new VideoCaptureDevice, storing the result in
-  // |entry->video_capture_device|.
+  // |entry->video_capture_device|. Ownership of |handler| passes to
+  // the device.
   void DoStartDeviceOnDeviceThread(
       DeviceEntry* entry,
       const media::VideoCaptureCapability& capture_params,
-      media::VideoCaptureDevice::EventHandler* controller_as_handler);
+      scoped_ptr<media::VideoCaptureDevice::EventHandler> handler);
 
   // Stop and destroy the VideoCaptureDevice held in
   // |entry->video_capture_device|.
   void DoStopDeviceOnDeviceThread(DeviceEntry* entry);
 
-  // Helper to clean up the DeviceEntry* instance, and the
-  // VideoCaptureController, on the IO thread. Must happen after
-  // DoStopDeviceOnDeviceThread() destroys the VideoCaptureDevice. It is assumed
-  // that |dead_device| has already been removed from the |devices_| map.
-  void FreeDeviceEntryOnIOThread(scoped_ptr<DeviceEntry> dead_device);
-
   // The message loop of media stream device thread, where VCD's live.
   scoped_refptr<base::MessageLoopProxy> device_loop_;
 
@@ -176,14 +174,14 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
   struct DeviceEntry {
     DeviceEntry(MediaStreamType stream_type,
                 const std::string& id,
-                scoped_refptr<VideoCaptureController> controller);
+                scoped_ptr<VideoCaptureController> controller);
     ~DeviceEntry();
 
     const MediaStreamType stream_type;
     const std::string id;
 
     // The controller. Only used from the IO thread.
-    scoped_refptr<VideoCaptureController> video_capture_controller;
+    scoped_ptr<VideoCaptureController> video_capture_controller;
 
     // The capture device. Only used from the device thread.
     scoped_ptr<media::VideoCaptureDevice> video_capture_device;