Add Media device notification to SystemMonitor and Mac impl

content/content_browser.gypi

Index: content/content_browser.gypi
diff --git a/content/content_browser.gypi b/content/content_browser.gypi
index 9e56c02c2700a6a23247d3bb1dd3a3c5cde663cc..7e8edc9d476f69d324f4ad1bac6d4f6d0e2b2fef 100644
--- a/content/content_browser.gypi
+++ b/content/content_browser.gypi
@@ -374,6 +374,8 @@
     'browser/load_from_memory_cache_details.cc',
     'browser/load_from_memory_cache_details.h',
     'browser/load_notification_details.h',
+    'browser/mac/media_device_notifications.h',
+    'browser/mac/media_device_notifications.mm',
     'browser/mach_broker_mac.cc',
     'browser/mach_broker_mac.h',
     'browser/mime_registry_message_filter.cc',
@@ -784,6 +786,11 @@
         '../third_party/mozilla/NSPasteboard+Utils.h',
         '../third_party/mozilla/NSPasteboard+Utils.mm',
       ],
+      'link_settings': {
+        'libraries': [
+          '$(SDKROOT)/System/Library/Frameworks/DiskArbitration.framework',
+        ],
+      },
       'dependencies': [
         'closure_blocks_leopard_compat',
       ],