Extract VideoCaptureDeviceFactory out of VideoCaptureDevice and use for File and FakeVCD.

content/browser/renderer_host/media/video_capture_manager.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.
 
 // VideoCaptureManager is used to open/close, start/stop, enumerate available
 // video capture devices, and manage VideoCaptureController's.
 // All functions are expected to be called from Browser::IO thread. Some helper
 // functions (*OnDeviceThread) will dispatch operations to the device thread.
 // VideoCaptureManager will open OS dependent instances of VideoCaptureDevice.
 // A device can only be opened once.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_
 
 #include <map>
 #include <set>
 #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"
 #include "content/common/content_export.h"
 #include "content/common/media/media_stream_options.h"
 #include "media/video/capture/video_capture_device.h"
+#include "media/video/capture/video_capture_device_factory.h"
 #include "media/video/capture/video_capture_types.h"
 
 namespace content {
 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.
@@ skipping 11 matching lines @@
 
   virtual void EnumerateDevices(MediaStreamType stream_type) OVERRIDE;
 
   virtual int Open(const StreamDeviceInfo& device) OVERRIDE;
 
   virtual void Close(int capture_session_id) OVERRIDE;
 
   // Used by unit test to make sure a fake device is used instead of a real
   // video capture device. Due to timing requirements, the function must be
   // called before EnumerateDevices and Open.
-  void UseFakeDevice();
+  void UseFakeDevice(scoped_ptr<media::VideoCaptureDeviceFactory> factory);

[perkj_chrome, 2014/04/15 09:34:01]

Why not just inject the factory in the ctor? Tests can inject fake version and
production the real one. You can have two ctors if you want the default ctor to
always create the default implementation of the factory.

[mcasas, 2014/04/15 13:47:09]

Extended the ctor to accept a Factory. 
Some higher level UTs (MediaStreamDispatcherHostTest,
VideoCaptureHostTest, MediaStreamManagerTest), 
manipulate MediaStreamManager that in turn manages
VCM, they create the MSM which injects a "normal" factory
and later call UseFakeVideoDevice, which changes the
 factory to Fake/File. This is suboptimal. 

 
   // Called by VideoCaptureHost to locate a capture device for |capture_params|,
   // adding the Host as a client of the device's controller if successful. The
   // value of |session_id| controls which device is selected;
   // this value should be a session id previously returned by Open().
   //
   // If the device is not already started (i.e., no other client is currently
   // capturing from this device), this call will cause a VideoCaptureController
   // and VideoCaptureDevice to be created, possibly asynchronously.
   //
@@ skipping 27 matching lines @@
   // |capture_session_id| is not found. Returns true and |formats_in_use|
   // otherwise. |formats_in_use| is empty if the device is not in use.
   bool GetDeviceFormatsInUse(media::VideoCaptureSessionId capture_session_id,
                              media::VideoCaptureFormats* formats_in_use);
 
   // Sets the platform-dependent window ID for the desktop capture notification
   // UI for the given session.
   void SetDesktopCaptureWindowId(media::VideoCaptureSessionId session_id,
                                  gfx::NativeViewId window_id);
 
+  // Gets a weak reference to the device factory, used for tests.
+  media::VideoCaptureDeviceFactory* video_capture_device_factory() const {
+    return video_capture_device_factory_.get();
+  }
+
  private:
   virtual ~VideoCaptureManager();
   struct DeviceEntry;
 
   // This data structure is a convenient wrap of a devices' name and associated
   // video capture supported formats.
   struct DeviceInfo {
     DeviceInfo();
     DeviceInfo(const media::VideoCaptureDevice::Name& name,
                const media::VideoCaptureFormats& supported_formats);
@@ skipping 97 matching lines @@
 
     // The controller. Only used from the IO thread.
     scoped_ptr<VideoCaptureController> video_capture_controller;
 
     // The capture device. Only used from the device thread.
     scoped_ptr<media::VideoCaptureDevice> video_capture_device;
   };
   typedef std::set<DeviceEntry*> DeviceEntries;
   DeviceEntries devices_;
 
+  scoped_ptr<media::VideoCaptureDeviceFactory> video_capture_device_factory_;
+
   // Local cache of the enumerated video capture devices' names and capture
   // supported formats. A snapshot of the current devices and their capabilities
   // is composed in GetAvailableDevicesInfoOnDeviceThread() --coming
   // from EnumerateDevices()--, and this snapshot is used to update this list in
   // OnDevicesInfoEnumerated(). GetDeviceSupportedFormats() will
   // use this list if the device is not started, otherwise it will retrieve the
   // active device capture format from the VideoCaptureController associated.
   DeviceInfos devices_info_cache_;
 
-  // For unit testing and for performance/quality tests, a test device can be
-  // used instead of a real one. The device can be a simple fake device (a
-  // rolling pacman), or a file that is played in a loop continuously. This only
-  // applies to the MEDIA_DEVICE_VIDEO_CAPTURE device type.
-  enum {
-    DISABLED,
-    TEST_PATTERN,
-    Y4M_FILE
-  } artificial_device_source_for_testing_;
+  // A test device can be used for unit testing and for performance/quality
+  // measurements. This device is usually injected from the test harness, but
+  // can also come from MediaStreamManager in normal operation, via command line
+  // flag. Supported test devices include a simple fake device (a rolling
+  // pacman), or a file that is played in a loop continuously. Test device is
+  // only and always of type MEDIA_DEVICE_VIDEO_CAPTURE.
+  bool use_testing_device_source_;

[perkj_chrome, 2014/04/15 09:34:01]

We want to get rid of this type of things in the production code. You should be
able to just have it in a test implemenetation of VideoCaptureDeviceFactory.

[mcasas, 2014/04/15 13:47:09]

Done.

 
   // Accessed on the device thread only.
   std::map<media::VideoCaptureSessionId, gfx::NativeViewId>
       notification_window_ids_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_