Change HungPluginTabHelper to listen for infobar changes through Observer style.

chrome/browser/ui/hung_plugin_tab_helper.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/ui/hung_plugin_tab_helper.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/process/process.h"
 #include "base/rand_util.h"
 #include "build/build_config.h"
-#include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/infobars/infobar_service.h"
 #include "chrome/common/chrome_version_info.h"
 #include "components/infobars/core/confirm_infobar_delegate.h"
 #include "components/infobars/core/infobar.h"
 #include "content/public/browser/browser_child_process_host_iterator.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/child_process_data.h"
-#include "content/public/browser/notification_details.h"
-#include "content/public/browser/notification_service.h"
 #include "content/public/browser/plugin_service.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/common/process_type.h"
 #include "content/public/common/result_codes.h"
 #include "grit/chromium_strings.h"
 #include "grit/generated_resources.h"
 #include "grit/locale_settings.h"
 #include "grit/theme_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 
@@ skipping 222 matching lines @@
 HungPluginTabHelper::PluginState::~PluginState() {
 }
 
 
 // HungPluginTabHelper --------------------------------------------------------
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(HungPluginTabHelper);
 
 HungPluginTabHelper::HungPluginTabHelper(content::WebContents* contents)
     : content::WebContentsObserver(contents) {
-  registrar_.Add(this, chrome::NOTIFICATION_TAB_CONTENTS_INFOBAR_REMOVED,
-                 content::NotificationService::AllSources());
 }
 
 HungPluginTabHelper::~HungPluginTabHelper() {
 }
 
 void HungPluginTabHelper::PluginCrashed(const base::FilePath& plugin_path,
                                         base::ProcessId plugin_pid) {
   // TODO(brettw) ideally this would take the child process ID. When we do this
   // for NaCl plugins, we'll want to know exactly which process it was since
   // the path won't be useful.
@@ skipping 37 matching lines @@
 
   base::string16 plugin_name =
       content::PluginService::GetInstance()->GetPluginDisplayNameByPath(
           plugin_path);
 
   linked_ptr<PluginState> state(new PluginState(plugin_path, plugin_name));
   hung_plugins_[plugin_child_id] = state;
   ShowBar(plugin_child_id, state.get());
 }
 
-void HungPluginTabHelper::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  DCHECK_EQ(chrome::NOTIFICATION_TAB_CONTENTS_INFOBAR_REMOVED, type);
-  infobars::InfoBar* infobar =
-      content::Details<infobars::InfoBar::RemovedDetails>(details)->first;
-  for (PluginStateMap::iterator i = hung_plugins_.begin();
-       i != hung_plugins_.end(); ++i) {
-    PluginState* state = i->second.get();
-    if (state->infobar == infobar) {
-      state->infobar = NULL;
-
-      // Schedule the timer to re-show the infobar if the plugin continues to be
-      // hung.
-      state->timer.Start(FROM_HERE, state->next_reshow_delay,
-          base::Bind(&HungPluginTabHelper::OnReshowTimer,
-                     base::Unretained(this),
-                     i->first));
-
-      // Next time we do this, delay it twice as long to avoid being annoying.
-      state->next_reshow_delay *= 2;
-      return;
-    }
-  }
-}
-
 void HungPluginTabHelper::KillPlugin(int child_id) {
 #if defined(OS_WIN)
   // Dump renderers that are sending or receiving pepper messages, in order to
   // diagnose inter-process deadlocks.
   // Only do that on the Canary channel, for 20% of pepper plugin hangs.
   if (base::RandInt(0, 100) < 20) {
     chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
     if (channel == chrome::VersionInfo::CHANNEL_CANARY) {
       scoped_ptr<OwnedHandleVector> renderer_handles(new OwnedHandleVector);
       HANDLE current_process = ::GetCurrentProcess();
@@ skipping 41 matching lines @@
   DCHECK(!found->second->infobar);
   ShowBar(child_id, found->second.get());
 }
 
 void HungPluginTabHelper::ShowBar(int child_id, PluginState* state) {
   InfoBarService* infobar_service =
       InfoBarService::FromWebContents(web_contents());
   if (!infobar_service)
     return;
 
+  infobar_service->AddObserver(this);

[tfarina, 2014/05/25 21:53:30]

I can't put this in the ctor, because otherwise, when the user shutdown the
browser this happens:

[15141:15141:0525/184807:FATAL:observer_list.h(197)] Check failed:
ObserverListBase<ObserverType>::size() == 0U (1 vs. 0)
#0 0x7f8071eb105e base::debug::StackTrace::StackTrace()
#1 0x7f8071f3e465 logging::LogMessage::~LogMessage()
#2 0x7f8077339b25 ObserverList<>::~ObserverList()
#3 0x7f8077338d35 infobars::InfoBarManager::~InfoBarManager()
#4 0x7f80745c70b2 InfoBarService::~InfoBarService()
#6 0x7f80745c71fc InfoBarService::~InfoBarService()
#7 0x7f8071ffb657 linked_ptr<>::depart()
#8 0x7f8071ffac45 linked_ptr<>::~linked_ptr()
#9 0x7f8071ffb21c std::pair<>::~pair()
#10 0x7f8071ffb1ec std::_Rb_tree_node<>::~_Rb_tree_node()
#11 0x7f8071ffb159 __gnu_cxx::new_allocator<>::destroy<>()
#12 0x7f8071ffb10c std::_Rb_tree<>::_M_destroy_node()
#13 0x7f8071ffb0be std::_Rb_tree<>::_M_erase_aux()
#14 0x7f8071ffb03a std::_Rb_tree<>::erase()
#15 0x7f8071ffafd5 std::__cxx1998::map<>::erase()
#16 0x7f8071ffacff std::__debug::map<>::erase()
#17 0x7f8071ffa4c1 base::SupportsUserData::RemoveUserData()
#18 0x7f80745c7510 InfoBarService::WebContentsDestroyed()
#19 0x7f80745c753c InfoBarService::WebContentsDestroyed()
#20 0x7f8065623224 content::WebContentsImpl::~WebContentsImpl()
#21 0x7f8065623989 content::WebContentsImpl::~WebContentsImpl()
#22 0x7f8076248fd7 TabStripModel::InternalCloseTab()
#23 0x7f80762453f8 TabStripModel::InternalCloseTabs()
#24 0x7f8076244f17 TabStripModel::CloseAllTabs()

[Peter Kasting, 2014/05/26 21:16:12]

You should only be doing this if we're not already an observer.  Based on the
other code in this file I assume we can be observing for multiple different
infobars.

+
   DCHECK(!state->infobar);
   state->infobar = HungPluginInfoBarDelegate::Create(infobar_service, this,
                                                      child_id, state->name);
 }
 
 void HungPluginTabHelper::CloseBar(PluginState* state) {

[tfarina, 2014/05/25 21:53:30]

should I have a call to RemoveObserver() here to balance the call to
AddObserver() in ShowBar?

[Peter Kasting, 2014/05/26 21:16:12]

All AddObserver() calls should be balanced with RemoveObserver() calls.

I don't think putting such a call here is right unless this is reached when
users click the close button on the infobar itself.  Otherwise you'll need to do
the call e.g. in OnInfoBarRemoved() when we have no more infobars.

   InfoBarService* infobar_service =
       InfoBarService::FromWebContents(web_contents());
   if (infobar_service && state->infobar) {
     infobar_service->RemoveInfoBar(state->infobar);
     state->infobar = NULL;
   }
 }
+
+void HungPluginTabHelper::OnInfoBarRemoved(infobars::InfoBar* infobar,
+                                           bool animate) {
+  for (PluginStateMap::iterator i = hung_plugins_.begin();
+       i != hung_plugins_.end(); ++i) {
+    PluginState* state = i->second.get();
+    if (state->infobar == infobar) {
+      state->infobar = NULL;
+
+      // Schedule the timer to re-show the infobar if the plugin continues to be
+      // hung.
+      state->timer.Start(FROM_HERE,
+                         state->next_reshow_delay,
+                         base::Bind(&HungPluginTabHelper::OnReshowTimer,
+                                    base::Unretained(this),
+                                    i->first));
+
+      // Next time we do this, delay it twice as long to avoid being annoying.
+      state->next_reshow_delay *= 2;
+      return;
+    }
+  }
+}
+
+void HungPluginTabHelper::OnManagerShuttingDown(
+    infobars::InfoBarManager* manager) {
+  InfoBarService* infobar_service =
+      InfoBarService::FromWebContents(web_contents());
+  if (infobar_service)
+    infobar_service->RemoveObserver(this);
+}