Fix plug-in identifier for Shockwave and add a unit test.

chrome/browser/plugin_observer.cc

 // 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 "chrome/browser/plugin_observer.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/stl_util.h"
 #include "base/utf_string_conversions.h"
@@ skipping 200 matching lines @@
   NOTREACHED();
 #endif  // defined(ENABLE_PLUGIN_INSTALLATION)
 }
 
 #if defined(ENABLE_PLUGIN_INSTALLATION)
 void PluginObserver::FindPluginToUpdate(int placeholder_id,
                                         const std::string& identifier,
                                         PluginFinder* plugin_finder) {
   PluginInstaller* installer =
       plugin_finder->FindPluginWithIdentifier(identifier);
-  // TODO(bauerb): Remove this CHECK once http://crbug.com/121657 is fixed.
-  CHECK(installer) << "Couldn't find PluginInstaller for identifier "
-                   << identifier;
+  DCHECK(installer) << "Couldn't find PluginInstaller for identifier "
+                    << identifier;
   plugin_placeholders_[placeholder_id] =
       new PluginPlaceholderHost(this, placeholder_id, installer);
   InfoBarTabHelper* infobar_helper = tab_contents_->infobar_tab_helper();
   infobar_helper->AddInfoBar(
       OutdatedPluginInfoBarDelegate::Create(this, installer));
 }
 
 void PluginObserver::OnFindMissingPlugin(int placeholder_id,
                                          const std::string& mime_type) {
 PluginFinder::Get(base::Bind(&PluginObserver::FindMissingPlugin,
@@ skipping 43 matching lines @@
 }
 #endif  // defined(ENABLE_PLUGIN_INSTALLATION)
 
 void PluginObserver::OnOpenAboutPlugins() {
     web_contents()->OpenURL(OpenURLParams(
         GURL(chrome::kAboutPluginsURL),
         content::Referrer(web_contents()->GetURL(),
                           WebKit::WebReferrerPolicyDefault),
         NEW_FOREGROUND_TAB, content::PAGE_TRANSITION_TYPED, false));
 }