Add support for dark theme in Mac Notification Center

base/mac/sdk_forward_declarations.h

Index: base/mac/sdk_forward_declarations.h
diff --git a/base/mac/sdk_forward_declarations.h b/base/mac/sdk_forward_declarations.h
index 649d57248970f4eda0bf631f282e6d30f4b5948e..a513706c868985408a0d45446886f0820b5c10c6 100644
--- a/base/mac/sdk_forward_declarations.h
+++ b/base/mac/sdk_forward_declarations.h
@@ -263,8 +263,17 @@ enum {
 + (BOOL)screensHaveSeparateSpaces;
 @end
 
+// NSAppearance is a new class in the 10.9 SDK. New classes cannot be
+// forward-declared because they also require an @implementation, which would
+// produce conflicting linkage. Instead, just declare the necessary pieces of
+// the interface as a protocol, and treat objects of this type as id.
+@protocol CrNSAppearance<NSObject>
++ (id<NSObject>)appearanceNamed:(NSString*)name;
+@end
+
 @interface NSView (MavericksSDK)
 - (void)setCanDrawSubviewsIntoLayer:(BOOL)flag;
+- (id<CrNSAppearance>)effectiveAppearance;
 @end
 
 enum {
@@ -310,6 +319,8 @@ BASE_EXPORT extern "C" NSString* const kCWSSIDDidChangeNotification;
 
 BASE_EXPORT extern "C" NSString* const NSUserActivityTypeBrowsingWeb;
 
+BASE_EXPORT extern "C" NSString* const NSAppearanceNameVibrantDark;
+
 #endif  // MAC_OS_X_VERSION_10_10
 
 #endif  // BASE_MAC_SDK_FORWARD_DECLARATIONS_H_