Fix RenderWidgetHostViewGuest leak.

chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.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/renderer_host/chrome_render_widget_host_view_mac_delegate.h"
 
 #include <cmath>
 
 #include "base/prefs/pref_service.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 58 matching lines @@
 };
 
 }  // namespace ChromeRenderWidgetHostViewMacDelegateInternal
 
 @implementation ChromeRenderWidgetHostViewMacDelegate
 
 - (id)initWithRenderWidgetHost:(content::RenderWidgetHost*)renderWidgetHost {
   self = [super init];
   if (self) {
     renderWidgetHost_ = renderWidgetHost;
-    NSView* nativeView = renderWidgetHost_->GetView()->GetNativeView();
-    view_id_util::SetID(nativeView, VIEW_ID_TAB_CONTAINER);
+    // if |renderWidgetHost_| belongs to a BrowserPluginGuest, then it won't
+    // have a view yet.
+    if (renderWidgetHost_->GetView()) {
+      NSView* nativeView = renderWidgetHost_->GetView()->GetNativeView();
+      view_id_util::SetID(nativeView, VIEW_ID_TAB_CONTAINER);
+    }
 
     if (renderWidgetHost_->IsRenderView()) {
       spellingObserver_.reset(
           new ChromeRenderWidgetHostViewMacDelegateInternal::SpellCheckObserver(
               RenderViewHost::From(renderWidgetHost_), self));
     }
 
     historySwiper_.reset([[HistorySwiper alloc] initWithDelegate:self]);
   }
   return self;
@@ skipping 164 matching lines @@
 }
 
 - (void)spellCheckEnabled:(BOOL)enabled checked:(BOOL)checked {
   spellcheckEnabled_ = enabled;
   spellcheckChecked_ = checked;
 }
 
 // END Spellchecking methods
 
 @end