Remove all the OS X 10.6 SDK forward declarations.

chrome/browser/ui/cocoa/base_bubble_controller.mm

Index: chrome/browser/ui/cocoa/base_bubble_controller.mm
diff --git a/chrome/browser/ui/cocoa/base_bubble_controller.mm b/chrome/browser/ui/cocoa/base_bubble_controller.mm
index fc6738ab590a9b6c51db5915491dd3aa4252b5c6..431c05587848681aee70bdaac8cbe0a14d81dfd5 100644
--- a/chrome/browser/ui/cocoa/base_bubble_controller.mm
+++ b/chrome/browser/ui/cocoa/base_bubble_controller.mm
@@ -6,7 +6,6 @@
 
 #include "base/logging.h"
 #include "base/mac/bundle_locations.h"
-#include "base/mac/closure_blocks_leopard_compat.h"
 #include "base/mac/mac_util.h"
 #include "base/memory/scoped_nsobject.h"
 #include "base/string_util.h"
@@ -24,28 +23,6 @@
                     userGesture:(bool)wasUserGesture;
 @end
 
-#if !defined(MAC_OS_X_VERSION_10_6) || \
-    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6
-typedef unsigned long long NSEventMask;
-
-@interface NSEvent (SnowLeopardDeclarations)
-+ (id)addLocalMonitorForEventsMatchingMask:(NSEventMask)mask
-                                   handler:(NSEvent* (^)(NSEvent*))block;
-+ (void)removeMonitor:(id)eventMonitor;
-@end
-
-@interface NSOperationQueue (SnowLeopardDeclarations)
-+ (id)mainQueue;
-@end
-
-@interface NSNotificationCenter (SnowLeopardDeclarations)
-- (id)addObserverForName:(NSString*)name
-                  object:(id)obj
-                   queue:(NSOperationQueue*)queue
-              usingBlock:(void (^)(NSNotification*))block;
-@end
-#endif  // MAC_OS_X_VERSION_10_6
-
 @implementation BaseBubbleController
 
 @synthesize parentWindow = parentWindow_;