Fix OSX 10.12 compilation errors in chrome/browser/ui.

chrome/browser/ui/cocoa/browser_window_fullscreen_transition.mm

Index: chrome/browser/ui/cocoa/browser_window_fullscreen_transition.mm
diff --git a/chrome/browser/ui/cocoa/browser_window_fullscreen_transition.mm b/chrome/browser/ui/cocoa/browser_window_fullscreen_transition.mm
index 5b6542a32d435c67991745a8a982d46bf8f70ccc..df3968b4e6901147c7d9792297b5b4196d634a5c 100644
--- a/chrome/browser/ui/cocoa/browser_window_fullscreen_transition.mm
+++ b/chrome/browser/ui/cocoa/browser_window_fullscreen_transition.mm
@@ -88,7 +88,8 @@ class FrameAndStyleLock {
 
 @end
 
-@interface BrowserWindowFullscreenTransition () {
+@interface BrowserWindowFullscreenTransition ()
+    <CAAnimationDelegate, CALayerDelegate> {
   // Flag to keep track of whether we are entering or exiting fullscreen.
   BOOL isEnteringFullscreen_;
 
@@ -164,7 +165,8 @@ class FrameAndStyleLock {
 // Sets |primaryWindow_|'s frame to the expected frame.
 - (void)changePrimaryWindowToFinalFrame;
 
-// Override of CAAnimation delegate method.
+// Overrides of CAAnimation delegate methods.
+- (void)animationDidStart:(CAAnimation*)theAnimation;
 - (void)animationDidStop:(CAAnimation*)theAnimation finished:(BOOL)finished;
 
 // Returns the layer of the root view of |window|.
@@ -482,6 +484,10 @@ class FrameAndStyleLock {
   changingPrimaryWindowSize_ = NO;
 }
 
+- (void)animationDidStart:(CAAnimation*)theAnimation {
+  // CAAnimationDelegate method added on OSX 10.12.
+}
+
 - (void)animationDidStop:(CAAnimation*)theAnimation finished:(BOOL)finished {
   NSString* animationID = [theAnimation valueForKey:kAnimationIDKey];