Make sure RenderWidgetHostViewCocoa doesn't disappear inside of -keyEvent:

chrome/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2006-2008 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 "chrome/browser/renderer_host/render_widget_host_view_mac.h"
 
 #include "base/histogram.h"
-#include "base/scoped_nsobject.h"
+#import "base/scoped_nsobject.h"
 #include "base/string_util.h"
 #include "base/sys_string_conversions.h"
 #include "chrome/browser/browser_trial.h"
 #import "chrome/browser/cocoa/rwhvm_editcommand_helper.h"
 #include "chrome/browser/renderer_host/backing_store.h"
 #include "chrome/browser/renderer_host/render_process_host.h"
 #include "chrome/browser/renderer_host/render_widget_host.h"
 #include "chrome/browser/spellchecker_platform_engine.h"
 #include "chrome/common/native_web_keyboard_event.h"
 #include "chrome/common/edit_command.h"
@@ skipping 518 matching lines @@
 }
 
 - (void)setIgnoreKeyEvents:(BOOL)ignorekeyEvents {
   ignoreKeyEvents_ = ignorekeyEvents;
 }
 
 - (BOOL)performKeyEquivalent:(NSEvent*)theEvent {
   if (ignoreKeyEvents_)
     return NO;
 
-  // We have some magic in |CrApplication sendEvent:| that always sends key 
+  // We have some magic in |CrApplication sendEvent:| that always sends key
   // events to |keyEvent:| so that cocoa doesn't have a chance to intercept it.
   DCHECK([[self window] firstResponder] != self);
   return NO;
 }
 
 - (void)keyEvent:(NSEvent*)theEvent {
   if (ignoreKeyEvents_)
     return;
 
-  // TODO(avi): Possibly kill self? See RenderWidgetHostViewWin::OnKeyEvent and
-  // http://b/issue?id=1192881 .
+  scoped_nsobject<RenderWidgetHostViewCocoa> keepSelfAlive([self retain]);

[pink (ping after 24hrs), 2009/10/28 19:56:40]

in mozilla these were generally named kungFuDeathGrip with nsCOMPtr :=)

 
   // Don't cancel child popups; the key events are probably what's triggering
   // the popup in the first place.
 
   NativeWebKeyboardEvent event(theEvent);
 
   // Save the modifier keys so the insertText method can use it when it sends
   // a Char event, which is dispatched as an onkeypress() event of JavaScript.
   renderWidgetHostView_->im_modifiers_ = event.modifiers;
 
@@ skipping 15 matching lines @@
     [EditCommandMatcher matchEditCommands:&editCommands forEvent:theEvent];
     if (!editCommands.empty())
       widgetHost->ForwardEditCommandsForNextKeyEvent(editCommands);
     widgetHost->ForwardKeyboardEvent(event);
   }
 
   // Dispatch a NSKeyDown event to an input method.
   // To send an onkeydown() event before an onkeypress() event, we should
   // dispatch this NSKeyDown event AFTER sending it to the renderer.
   // (See <https://bugs.webkit.org/show_bug.cgi?id=25119>).
-  if ([theEvent type] == NSKeyDown)
+  //
+  // If this object's retainCount is 1, the only reference is the one held by
+  // keepSelfAlive.  All other references may have been destroyed in the
+  // RenderWidgetHost::ForwardKeyboardEvent call above if it resulted in tab
+  // closure.  Were it not for that single reference, this object would
+  // already be deallocated.  In that case, there's no point in calling
+  // -interpretKeyEvents:.
+  if ([self retainCount] > 1 && [theEvent type] == NSKeyDown)
     [self interpretKeyEvents:[NSArray arrayWithObject:theEvent]];
 
   // Possibly autohide the cursor.
   if ([RenderWidgetHostViewCocoa shouldAutohideCursorForEvent:theEvent])
     [NSCursor setHiddenUntilMouseMoves:YES];
 }
 
 - (void)scrollWheel:(NSEvent *)theEvent {
   [self cancelChildPopups];
 
@@ skipping 643 matching lines @@
                                  base::Time::Now().ToDoubleT());
     renderWidgetHostView_->render_widget_host_->ForwardKeyboardEvent(event);
   } else {
     renderWidgetHostView_->render_widget_host_->ImeConfirmComposition(
         UTF8ToUTF16([im_text UTF8String]));
   }
   renderWidgetHostView_->im_composing_ = false;
 }
 
 @end
-