[Extensions UI] Fix a crash when clicking on a bubble's learn more

chrome/browser/extensions/extension_message_bubble_controller.cc

 // Copyright (c) 2013 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/extensions/extension_message_bubble_controller.h"
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 206 matching lines @@
   delegate_->LogAction(user_action_);
 
   OnClose();
 }
 
 void ExtensionMessageBubbleController::OnLinkClicked() {
   DCHECK_EQ(ACTION_BOUNDARY, user_action_);
   user_action_ = ACTION_LEARN_MORE;
 
   delegate_->LogAction(ACTION_LEARN_MORE);
+  // Opening a new tab for the learn more link can cause the bubble to close, so
+  // perform our cleanup here before opening the new tab.
+  OnClose();
   if (!g_should_ignore_learn_more_for_testing) {
     browser_->OpenURL(
         content::OpenURLParams(delegate_->GetLearnMoreUrl(),
                                content::Referrer(),
                                NEW_FOREGROUND_TAB,
                                ui::PAGE_TRANSITION_LINK,
                                false));
   }
-  OnClose();
+  // Warning: |this| may be deleted here!
 }
 
 void ExtensionMessageBubbleController::SetIsActiveBubble() {
   DCHECK(!is_active_bubble_);
   DCHECK(!model_->has_active_bubble());
   is_active_bubble_ = true;
   model_->set_has_active_bubble(true);
 }
 
 void ExtensionMessageBubbleController::ClearProfileListForTesting() {
@@ skipping 57 matching lines @@
     if (delegate_->ClearProfileSetAfterAction())
       GetProfileSet()->clear();
   }
 }
 
 std::set<Profile*>* ExtensionMessageBubbleController::GetProfileSet() {
   return &g_shown_for_profiles.Get()[delegate_->GetKey()];
 }
 
 }  // namespace extensions