Added AVFoundation Glue and Device Monitoring for Mac.

media/video/capture/mac/avfoundation_glue.h

+// Copyright 2013 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.
+
+// AVFoundation API is only introduced in Mac OS X > 10.6, and there is only one
+// build of Chromium, so the (potential) linking with AVFoundation has to happen
+// in runtime. For this to be clean, a AVFoundationGlue class is defined to try
+// and load these AVFoundation system libraries. If it succeeds, subsequent
+// clients can use AVFoundation via the rest of the classes declared in this
+// file.
+
+#ifndef MEDIA_VIDEO_CAPTURE_MAC_AVFOUNDATION_GLUE_H_
+#define MEDIA_VIDEO_CAPTURE_MAC_AVFOUNDATION_GLUE_H_
+
+#import <Foundation/Foundation.h>
+
+#include "base/basictypes.h"
+#include "media/base/media_export.h"
+
+class MEDIA_EXPORT AVFoundationGlue {
+ public:
+  // This method returns YES if the OS version supports AVFoundation and the
+  // AVFoundation bundle could be loaded correctly, or NO otherwise.
+  static BOOL isAVFoundationSupported();

[Robert Sesek, 2013/10/14 17:26:44]

C++ naming uses capitalization of the first character, i.e.
IsAVFoundationSupported(). Here and throughout.

[mcasas, 2013/10/15 11:50:11]

Done.

+
+  static NSBundle const* avFoundationBundle();
+
+  static void* avFoundationLibraryHandle();
+
+  // Originally coming from AVCaptureDevice.h but in global namespace.
+  static NSString* avCaptureDeviceWasConnectedNotification();
+  static NSString* avCaptureDeviceWasDisconnectedNotification();
+
+  // Originally coming from AVMediaFormat.h but in global namespace.
+  static NSString* avMediaTypeVideo();
+  static NSString* avMediaTypeAudio();
+  static NSString* avMediaTypeMuxed();
+
+  static NSString* readNSStringPtr(char const* const symbol,
+                                   void* const handle);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(AVFoundationGlue);
+};
+
+// Originally AVCaptureDevice and coming from AVCaptureDevice.h
+@interface CrAVCaptureDevice : NSObject
+
+- (BOOL)hasMediaType:(NSString const*)mediaType;
+
+- (NSString*)uniqueID;
+
+@end
+
+@interface AVCaptureDeviceGlue : NSObject
+
++ (NSArray*)devices;
+
++ (BOOL)hasMediaType:(NSString const*)mediaType
+    forCaptureDevice:(CrAVCaptureDevice const*)device;
+
++ (NSString*)uniqueID:(CrAVCaptureDevice const*)device;
+
+@end
+
+#endif  // MEDIA_VIDEO_CAPTURE_MAC_AVFOUNDATION_GLUE_H_