Fixing crasher with deleted content still being present in our ChromeLauncherController's |web_contents_to_app_id_| list

BUG=359037
TEST=none since the exact condition how to get there is still unknown

Review URL: https://codereview.chromium.org/223403010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@261919 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 35 insertions, 8 deletions

diff --git a/chrome/browser/ui/ash/launcher/browser_status_monitor.cc b/chrome/browser/ui/ash/launcher/browser_status_monitor.cc
index 285d0fc..7d8123d 100644
--- a/chrome/browser/ui/ash/launcher/browser_status_monitor.cc
+++ b/chrome/browser/ui/ash/launcher/browser_status_monitor.cc
@@ -55,6 +55,16 @@ void BrowserStatusMonitor::LocalWebContentsObserver::DidNavigateMainFrame(
   }
 }
 
+void BrowserStatusMonitor::LocalWebContentsObserver::WebContentsDestroyed(
+    content::WebContents* web_content) {
+  if (web_content == web_contents()) {
+    // We can only come here when there was a non standard termination like
+    // an app got un-installed while running, etc.
+    monitor_->WebContentsDestroyed(web_content);
+    // |this| is gone now.
+  }
+}
+
 BrowserStatusMonitor::BrowserStatusMonitor(
     ChromeLauncherController* launcher_controller)
     : launcher_controller_(launcher_controller),
@@ -106,9 +116,11 @@ void BrowserStatusMonitor::UpdateAppItemState(
     ChromeLauncherController::AppState app_state) {
   DCHECK(contents);
   // It is possible to come here from Browser::SwapTabContent where the contents
-  // cannot be associated with a browser.
+  // cannot be associated with a browser. A removal however should be properly
+  // processed.
   Browser* browser = chrome::FindBrowserWithWebContents(contents);
-  if (browser && launcher_controller_->IsBrowserFromActiveUser(browser))
+  if (app_state == ChromeLauncherController::APP_STATE_REMOVED ||
+      (browser && launcher_controller_->IsBrowserFromActiveUser(browser)))
     launcher_controller_->UpdateAppState(contents, app_state);
 }
 
@@ -288,6 +300,12 @@ void BrowserStatusMonitor::TabClosingAt(TabStripModel* tab_strip_mode,
   RemoveWebContentsObserver(contents);
 }
 
+void BrowserStatusMonitor::WebContentsDestroyed(
+    content::WebContents* contents) {
+  UpdateAppItemState(contents, ChromeLauncherController::APP_STATE_REMOVED);
+  RemoveWebContentsObserver(contents);
+}
+
 void BrowserStatusMonitor::AddV1AppToShelf(Browser* browser) {
   DCHECK(browser->is_type_popup() && browser->is_app());
 
diff --git a/chrome/browser/ui/ash/launcher/browser_status_monitor.h b/chrome/browser/ui/ash/launcher/browser_status_monitor.h
index 6e54ac2..fd1d205 100644
--- a/chrome/browser/ui/ash/launcher/browser_status_monitor.h
+++ b/chrome/browser/ui/ash/launcher/browser_status_monitor.h
@@ -88,6 +88,11 @@ class BrowserStatusMonitor : public aura::client::ActivationChangeObserver,
                             content::WebContents* contents,
                             int index) OVERRIDE;
 
+  // Called from our own |LocalWebContentsObserver| when web contents did go
+  // away without any other notification. This might happen in case of
+  // application uninstalls, page crashes, ...).
+  void WebContentsDestroyed(content::WebContents* web_contents);
+
  protected:
   // Add a V1 application to the shelf. This can get overwritten for multi
   // profile implementations.
@@ -113,6 +118,8 @@ class BrowserStatusMonitor : public aura::client::ActivationChangeObserver,
     virtual void DidNavigateMainFrame(
         const content::LoadCommittedDetails& details,
         const content::FrameNavigateParams& params) OVERRIDE;
+    virtual void WebContentsDestroyed(
+        content::WebContents* web_contents) OVERRIDE;
 
    private:
     BrowserStatusMonitor* monitor_;
diff --git a/chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc b/chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc
index 25f83d9..0675094 100644
--- a/chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc
+++ b/chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc
@@ -1687,10 +1687,11 @@ ash::ShelfItemStatus ChromeLauncherController::GetAppState(
        ++it) {
     if (it->second == app_id) {
       Browser* browser = chrome::FindBrowserWithWebContents(it->first);
-      // There should never be an item in our |web_contents_to_app_id_| list
-      // which got deleted already. If it is, it is likely that
-      // BrowserStatusMonitor forgot to inform us of that change.
-      DCHECK(browser);
+      // Usually there should never be an item in our |web_contents_to_app_id_|
+      // list which got deleted already. However - in some situations e.g.
+      // Browser::SwapTabContent there is temporarily no associated browser.
+      if (!browser)
+        continue;
       if (browser->window()->IsActive()) {
         return browser->tab_strip_model()->GetActiveWebContents() == it->first ?
             ash::STATUS_ACTIVE : ash::STATUS_RUNNING;
diff --git a/chrome/browser/ui/ash/launcher/launcher_app_tab_helper.cc b/chrome/browser/ui/ash/launcher/launcher_app_tab_helper.cc
index 862bccc..fe6e5ff 100644
--- a/chrome/browser/ui/ash/launcher/launcher_app_tab_helper.cc
+++ b/chrome/browser/ui/ash/launcher/launcher_app_tab_helper.cc
@@ -28,12 +28,13 @@ const extensions::Extension* GetExtensionForTab(Profile* profile,
   if (!extension_service || !extension_service->extensions_enabled())
     return NULL;
 
+  // Note: It is possible to come here after a tab got removed form the browser
+  // before it gets destroyed, in which case there is no browser.
   Browser* browser = chrome::FindBrowserWithWebContents(tab);
-  DCHECK(browser);
 
   // Use the Browser's app name to determine the extension for app windows and
   // use the tab's url for app tabs.
-  if (browser->is_app()) {
+  if (browser && browser->is_app()) {
     return extension_service->GetInstalledExtension(
         web_app::GetExtensionIdFromApplicationName(browser->app_name()));
   }