Implemented fullscreen exit animation with AppKit

chrome/browser/ui/cocoa/framed_browser_window.mm

Index: chrome/browser/ui/cocoa/framed_browser_window.mm
diff --git a/chrome/browser/ui/cocoa/framed_browser_window.mm b/chrome/browser/ui/cocoa/framed_browser_window.mm
index 5d098be8d3c00a47cd7a24ab4c2703c7ba498748..1eede2ac6e89b9b31c88a4f1a795a8ca2565c4fd 100644
--- a/chrome/browser/ui/cocoa/framed_browser_window.mm
+++ b/chrome/browser/ui/cocoa/framed_browser_window.mm
@@ -102,6 +102,24 @@ const CGFloat kWindowGradientHeight = 24.0;
   return self;
 }
 
+// Overriding this method to prevent the OSX from automatically setting
+// the style mask
+- (void)setStyleMask:(NSUInteger)styleMask {
+    if (frameAndStyleLock_) {
+        return;
+    }
+    [super setStyleMask:styleMask];
+}
+
+// Overriding this method to prevent the OSX from automatically setting
+// the frame
+- (void)setFrame:(NSRect)frameRect display:(BOOL)flag animate:(BOOL)animateFlag {
+    if (frameAndStyleLock_) {
+        return;
+    }
+    [super setFrame:frameRect display:flag animate:animateFlag];
+}
+
 - (void)dealloc {
   [[NSNotificationCenter defaultCenter] removeObserver:self];
   [super dealloc];
@@ -177,6 +195,12 @@ const CGFloat kWindowGradientHeight = 24.0;
   shouldHideTitle_ = flag;
 }
 
+// This method sets a lock which prevents the the frame and style
+// of the window to be changed
+- (void) setFrameAndStyleLock:(BOOL)lock {
+  frameAndStyleLock_ = lock;
+}
+
 - (BOOL)_isTitleHidden {
   return shouldHideTitle_;
 }