Mac: Support default browser Handoff in Yosemite.

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 61b4a6a99912a42d36be6befbca0db78e9350e8a..fad141fbb9b11d36d5f3bfc9b649d7ae9cc586d0 100644
--- a/base/mac/sdk_forward_declarations.h
+++ b/base/mac/sdk_forward_declarations.h
@@ -254,4 +254,18 @@ typedef NSUInteger NSWindowOcclusionState;
 
 #endif  // MAC_OS_X_VERSION_10_9
 
+#if !defined(MAC_OS_X_VERSION_10_10) || \
+    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_10
+
+@interface NSUserActivity : NSObject
+
+@property (readonly, copy) NSString* activityType;
+@property (copy) NSURL* webPageURL;
+
+@end
+
+BASE_EXPORT extern "C" NSString* const NSUserActivityTypeBrowsingWeb;
+
+#endif  // MAC_OS_X_VERSION_10_10
+
 #endif  // BASE_MAC_SDK_FORWARD_DECLARATIONS_H_