Fix race condition if a pulsing bookmark button is deleted while the bookmark bubble controller is …

chrome/browser/ui/cocoa/bookmarks/bookmark_bubble_controller.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.
 
 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_bubble_controller.h"
 
 #include "base/mac/bundle_locations.h"
 #include "base/mac/mac_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/browser/bookmarks/bookmark_model.h"
@@ skipping 33 matching lines @@
   static ChooseAnotherFolder* object = nil;
   if (!object) {
     object = [[ChooseAnotherFolder alloc] init];
   }
   return object;
 }
 
 - (id)initWithParentWindow:(NSWindow*)parentWindow
                      model:(BookmarkModel*)model
                       node:(const BookmarkNode*)node
-     alreadyBookmarked:(BOOL)alreadyBookmarked {
+         alreadyBookmarked:(BOOL)alreadyBookmarked {
+  DCHECK(model);
+  DCHECK(node);
   if ((self = [super initWithWindowNibPath:@"BookmarkBubble"
                               parentWindow:parentWindow
                                 anchoredAt:NSZeroPoint])) {
     model_ = model;
     node_ = node;
     alreadyBookmarked_ = alreadyBookmarked;
   }
   return self;
 }
 
 - (void)awakeFromNib {
   [super awakeFromNib];
 
   [[nameTextField_ cell] setUsesSingleLineMode:YES];
 }
 
 // If this is a new bookmark somewhere visible (e.g. on the bookmark
 // bar), pulse it.  Else, call ourself recursively with our parent
 // until we find something visible to pulse.
 - (void)startPulsingBookmarkButton:(const BookmarkNode*)node  {
   while (node) {
     if ((node->parent() == model_->bookmark_bar_node()) ||
         (node == model_->other_node())) {
       pulsingBookmarkNode_ = node;
+      bookmarkObserver_->StartObservingNode(pulsingBookmarkNode_);
       NSValue *value = [NSValue valueWithPointer:node];
       NSDictionary *dict = [NSDictionary
                              dictionaryWithObjectsAndKeys:value,
                              bookmark_button::kBookmarkKey,
                              [NSNumber numberWithBool:YES],
                              bookmark_button::kBookmarkPulseFlagKey,
                              nil];
       [[NSNotificationCenter defaultCenter]
         postNotificationName:bookmark_button::kPulseBookmarkButtonNotification
                       object:self
                     userInfo:dict];
       return;
     }
     node = node->parent();
   }
 }
 
 - (void)stopPulsingBookmarkButton {
   if (!pulsingBookmarkNode_)
     return;
   NSValue *value = [NSValue valueWithPointer:pulsingBookmarkNode_];
+  if (bookmarkObserver_)
+      bookmarkObserver_->StopObservingNode(pulsingBookmarkNode_);
   pulsingBookmarkNode_ = NULL;
   NSDictionary *dict = [NSDictionary
                          dictionaryWithObjectsAndKeys:value,
                          bookmark_button::kBookmarkKey,
                          [NSNumber numberWithBool:NO],
                          bookmark_button::kBookmarkPulseFlagKey,
                          nil];
   [[NSNotificationCenter defaultCenter]
         postNotificationName:bookmark_button::kPulseBookmarkButtonNotification
                       object:self
                     userInfo:dict];
 }
 
 // Close the bookmark bubble without changing anything.  Unlike a
 // typical dialog's OK/Cancel, where Cancel is "do nothing", all
 // buttons on the bubble have the capacity to change the bookmark
 // model.  This is an IBOutlet-looking entry point to remove the
 // dialog without touching the model.
 - (void)dismissWithoutEditing:(id)sender {
   [self close];
 }
 
 - (void)windowWillClose:(NSNotification*)notification {
   // We caught a close so we don't need to watch for the parent closing.
-  bookmark_observer_.reset(NULL);
+  bookmarkObserver_.reset();
   [self stopPulsingBookmarkButton];
   [super windowWillClose:notification];
 }
 
 // Override -[BaseBubbleController showWindow:] to tweak bubble location and
 // set up UI elements.
 - (void)showWindow:(id)sender {
   NSWindow* window = [self window];  // Force load the NIB.
   NSWindow* parentWindow = self.parentWindow;
   BrowserWindowController* bwc =
@@ skipping 21 matching lines @@
         l10n_util::GetNSString(IDS_BOOKMARK_BUBBLE_PAGE_BOOKMARKED);
     [bigTitle_ setStringValue:title];
   }
 
   [self fillInFolderList];
 
   // Ping me when things change out from under us.  Unlike a normal
   // dialog, the bookmark bubble's cancel: means "don't add this as a
   // bookmark", not "cancel editing".  We must take extra care to not
   // touch the bookmark in this selector.
-  bookmark_observer_.reset(new BookmarkModelObserverForCocoa(
-                               node_, model_,
-                               self,
-                               @selector(dismissWithoutEditing:)));
+  bookmarkObserver_.reset(new BookmarkModelObserverForCocoa(
+      model_,
+      ^(BOOL nodeWasDeleted) {
+          // If a watched node was deleted, the pointer to the pulsing button
+          // is likely stale.
+          if (nodeWasDeleted)
+            pulsingBookmarkNode_ = NULL;
+          [self dismissWithoutEditing:nil];
+      }));
+  bookmarkObserver_->StartObservingNode(node_);
 
   // Pulse something interesting on the bookmark bar.
   [self startPulsingBookmarkButton:node_];
 
   [parentWindow addChildWindow:window ordered:NSWindowAbove];
   [window makeKeyAndOrderFront:self];
   [self registerKeyStateEventTap];
 }
 
 - (void)close {
@@ skipping 172 matching lines @@
   NSInteger idx = [menu indexOfItemWithRepresentedObject:parentValue];
   DCHECK(idx != -1);
   [folderPopUpButton_ selectItemAtIndex:idx];
 }
 
 - (NSPopUpButton*)folderPopUpButton {
   return folderPopUpButton_;
 }
 
 @end  // implementation BookmarkBubbleController(ExposedForUnitTesting)