Fix a crash when built with 10.7 SDK running on OS X 10.6

content/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2012 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.
 
 #include "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #include <QuartzCore/QuartzCore.h>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 2360 matching lines @@
 
   // If the new window for this view is using CoreAnimation then enable
   // CoreAnimation on this view.
   if (GetCoreAnimationStatus() == CORE_ANIMATION_ENABLED_LAZY &&
       [[newWindow contentView] wantsLayer]) {
     renderWidgetHostView_->EnableCoreAnimation();
   }
 
   NSNotificationCenter* notificationCenter =
       [NSNotificationCenter defaultCenter];
+
+  // Backing property notifications crash on 10.6 when building with the 10.7
+  // SDK, see http://crbug.com/260595.
+  BOOL supportsBackingPropertiesNotification = base::mac::IsOSLionOrLater();
+
   if (oldWindow) {
-    [notificationCenter
-        removeObserver:self
-                  name:NSWindowDidChangeBackingPropertiesNotification
-                object:oldWindow];
+    if (supportsBackingPropertiesNotification) {
+      [notificationCenter
+          removeObserver:self
+                    name:NSWindowDidChangeBackingPropertiesNotification
+                  object:oldWindow];
+    }
     [notificationCenter
         removeObserver:self
                   name:NSWindowDidMoveNotification
                 object:oldWindow];
     [notificationCenter
         removeObserver:self
                   name:NSWindowDidEndLiveResizeNotification
                 object:oldWindow];
   }
   if (newWindow) {
-    [notificationCenter
-        addObserver:self
-           selector:@selector(windowDidChangeBackingProperties:)
-               name:NSWindowDidChangeBackingPropertiesNotification
-             object:newWindow];
+    if (supportsBackingPropertiesNotification) {
+      [notificationCenter
+          addObserver:self
+             selector:@selector(windowDidChangeBackingProperties:)
+                 name:NSWindowDidChangeBackingPropertiesNotification
+               object:newWindow];
+    }
     [notificationCenter
         addObserver:self
            selector:@selector(windowChangedGlobalFrame:)
                name:NSWindowDidMoveNotification
              object:newWindow];
     [notificationCenter
         addObserver:self
            selector:@selector(windowChangedGlobalFrame:)
                name:NSWindowDidEndLiveResizeNotification
              object:newWindow];
@@ skipping 1317 matching lines @@
   return YES;
 }
 
 - (BOOL)isOpaque {
   if (renderWidgetHostView_->use_core_animation_)
     return YES;
   return [super isOpaque];
 }
 
 @end