Added AVFoundation Glue and Device Monitoring for Mac.

media/video/capture/mac/avfoundation_glue.mm

+// 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.
+
+#import "media/video/capture/mac/avfoundation_glue.h"
+
+#include <dlfcn.h>
+
+#include "base/mac/mac_util.h"
+
+BOOL AVFoundationGlue::isAVFoundationSupported() {
+  return (base::mac::IsOSLionOrLater() &&
+          [AVFoundationGlue::avFoundationBundle() load]);
+}
+
+NSBundle const* AVFoundationGlue::avFoundationBundle() {
+  static NSBundle* bundle = [NSBundle
+      bundleWithPath:@"/System/Library/Frameworks/AVFoundation.framework"];
+  return bundle;
+}
+
+void* AVFoundationGlue::avFoundationLibraryHandle() {
+  const char* library_path = [[AVFoundationGlue::avFoundationBundle()

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

You shouldn't need |AVFoundationGlue::| since you're calling another static
member of the same class. Here and throughout.

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

Done.

+      executablePath] fileSystemRepresentation];
+  if (library_path == NULL) {
+    DCHECK(FALSE);

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

FALSE -> false

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

Done.

+    return NULL;
+  }
+  static void* library_handle = dlopen(library_path, RTLD_LAZY | RTLD_LOCAL);
+  DCHECK(library_handle) << dlerror();
+  return library_handle;
+}
+
+NSString* AVFoundationGlue::avCaptureDeviceWasConnectedNotification() {
+  return AVFoundationGlue::readNSStringPtr(
+      "AVCaptureDeviceWasConnectedNotification",
+      AVFoundationGlue::avFoundationLibraryHandle());
+}
+
+NSString* AVFoundationGlue::avCaptureDeviceWasDisconnectedNotification() {
+  return AVFoundationGlue::readNSStringPtr(
+      "AVCaptureDeviceWasDisconnectedNotification",
+      AVFoundationGlue::avFoundationLibraryHandle());
+}
+
+NSString* AVFoundationGlue::avMediaTypeVideo() {
+  return AVFoundationGlue::readNSStringPtr(
+      "AVMediaTypeVideo", AVFoundationGlue::avFoundationLibraryHandle());
+}
+
+NSString* AVFoundationGlue::avMediaTypeAudio() {
+  return AVFoundationGlue::readNSStringPtr(
+      "AVMediaTypeAudio", AVFoundationGlue::avFoundationLibraryHandle());
+}
+
+NSString* AVFoundationGlue::avMediaTypeMuxed() {
+  return AVFoundationGlue::readNSStringPtr(
+      "AVMediaTypeMuxed", AVFoundationGlue::avFoundationLibraryHandle());
+}
+
+NSString* AVFoundationGlue::readNSStringPtr(char const* const symbol,
+                                            void* const handle) {
+  NSString** stringPointer = (NSString**)dlsym(handle, symbol);
+  DCHECK(stringPointer) << dlerror();
+  return *stringPointer;
+}
+
+@implementation AVCaptureDeviceGlue
+
++ (NSArray*)devices {
+  Class avcClass =
+      [AVFoundationGlue::avFoundationBundle() classNamed:@"AVCaptureDevice"];
+  SEL selectorDevices = NSSelectorFromString(@"devices");
+  if ([avcClass respondsToSelector:selectorDevices]) {
+    return [avcClass performSelector:selectorDevices];
+  }
+  return nil;
+}
+
++ (BOOL)hasMediaType:(NSString*)mediaType
+    forCaptureDevice:(CrAVCaptureDevice const*)device {
+  SEL selectorHasMediaType = NSSelectorFromString(@"hasMediaType:");
+  if ([device respondsToSelector:selectorHasMediaType]) {
+    return [device hasMediaType:mediaType];
+  }
+  return NO;
+}
+
++ (NSString*)uniqueID:(CrAVCaptureDevice const*)device {
+  SEL selectorUniqueID = NSSelectorFromString(@"uniqueID");
+  if ([device respondsToSelector:selectorUniqueID]) {
+    return [device uniqueID];
+  }
+  return nil;
+}
+
+@end  // @implementation AVCaptureDevice