Add a stack-based class for property disabling and re-enabling screen updating without epic fail. Fixes issues where we weren't re-enabling updates in many cases which caused both jank and resize issues.

BUG=13476
TEST=closing windows shouldn't have jank regardless of the # of tabs. Resizing a window shouldn't explode visually in the chrome.
Review URL: http://codereview.chromium.org/119363

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@17956 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 39 insertions, 4 deletions

diff --git a/base/base.gyp b/base/base.gyp
index b26c68e..5d09098 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -247,6 +247,7 @@
         'scoped_handle_win.h',
         'scoped_nsautorelease_pool.h',
         'scoped_nsautorelease_pool.mm',
+        'scoped_nsdisable_screen_updates.h',
         'scoped_nsobject.h',
         'scoped_ptr.h',
         'scoped_temp_dir.cc',
diff --git a/base/scoped_nsdisable_screen_updates.h b/base/scoped_nsdisable_screen_updates.h
new file mode 100644
index 0000000..3258fca
--- /dev/null
+++ b/base/scoped_nsdisable_screen_updates.h
@@ -0,0 +1,35 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_SCOPED_NSDISABLE_SCREEN_UPDATES_H_
+#define BASE_SCOPED_NSDISABLE_SCREEN_UPDATES_H_
+
+#import <Cocoa/Cocoa.h>
+
+#include "base/basictypes.h"
+
+namespace base {
+
+// A stack-based class to disable Cocoa screen updates. When instantiated, it
+// disables screen updates and enables them when destroyed. Update disabling
+// can be nested, and there is a time-maximum (about 1 second) after which
+// Cocoa will automatically re-enable updating. This class doesn't attempt to
+// overrule that.
+
+class ScopedNSDisableScreenUpdates {
+ public:
+  ScopedNSDisableScreenUpdates() {
+    NSDisableScreenUpdates();
+  }
+  ~ScopedNSDisableScreenUpdates() {
+    NSEnableScreenUpdates();
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ScopedNSDisableScreenUpdates);
+};
+
+}  // namespace
+
+#endif
diff --git a/chrome/browser/cocoa/browser_window_controller.mm b/chrome/browser/cocoa/browser_window_controller.mm
index 9fa2ee0..f8342d0 100644
--- a/chrome/browser/cocoa/browser_window_controller.mm
+++ b/chrome/browser/cocoa/browser_window_controller.mm
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "base/mac_util.h"
+#include "base/scoped_nsdisable_screen_updates.h"
 #include "base/sys_string_conversions.h"
 #include "chrome/app/chrome_dll_resource.h"  // IDC_*
 #include "chrome/browser/browser.h"
@@ -193,7 +194,7 @@ willPositionSheet:(NSWindow *)sheet
 // going away) will again call to close the window when it's finally ready.
 - (BOOL)windowShouldClose:(id)sender {
   // Disable updates while closing all tabs to avoid flickering.
-  NSDisableScreenUpdates();
+  base::ScopedNSDisableScreenUpdates disabler;
   // Give beforeunload handlers the chance to cancel the close before we hide
   // the window below.
   if (!browser_->ShouldCloseWindow())
@@ -212,7 +213,6 @@ willPositionSheet:(NSWindow *)sheet
     browser_->OnWindowClosing();
     return NO;
   }
-  NSEnableScreenUpdates();
 
   // the tab strip is empty, it's ok to close the window
   return YES;
@@ -462,7 +462,7 @@ willPositionSheet:(NSWindow *)sheet
 
 - (TabWindowController*)detachTabToNewWindow:(TabView*)tabView {
   // Disable screen updates so that this appears as a single visual change.
-  NSDisableScreenUpdates();
+  base::ScopedNSDisableScreenUpdates disabler;
 
   // Fetch the tab contents for the tab being dragged
   int index = [tabStripController_ indexForTabView:tabView];
@@ -507,7 +507,6 @@ willPositionSheet:(NSWindow *)sheet
   // And make sure we use the correct frame in the new view.
   [[controller tabStripController] setFrameOfSelectedTab:tabRect];
 
-  NSEnableScreenUpdates();
   return controller;
 }