Adding overview / layer framework to Activities so that unloaded / sleeping activities can be shown…

athena/content/app_activity_registry.cc

 // Copyright 2014 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 "athena/content/app_activity_registry.h"
 
 #include "athena/activity/public/activity_manager.h"
 #include "athena/content/app_activity.h"
 #include "athena/content/app_activity_proxy.h"
 #include "athena/content/public/app_registry.h"
 #include "athena/extensions/public/extensions_delegate.h"
 #include "athena/resource_manager/public/resource_manager.h"
 #include "athena/wm/public/window_list_provider.h"
 #include "athena/wm/public/window_manager.h"
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/single_thread_task_runner.h"
+#include "base/thread_task_runner_handle.h"
 #include "ui/aura/window.h"
 #include "ui/views/view.h"
 #include "ui/views/widget/widget.h"
 
 namespace athena {
 
 AppActivityRegistry::AppActivityRegistry(
     const std::string& app_id,
     content::BrowserContext* browser_context) :
       app_id_(app_id),
@@ skipping 47 matching lines @@
     if ((*it)->GetCurrentState() != Activity::ACTIVITY_UNLOADED)
       return;
   }
 
   // Create an activity proxy which can be used to re-activate the app. Insert
   // the proxy then into the activity stream at the location of the (newest)
   // current activity.
   unloaded_activity_proxy_ = new AppActivityProxy(GetMruActivity(), this);
   ActivityManager::Get()->AddActivity(unloaded_activity_proxy_);
 
-  // Unload the application. This operation will be asynchronous.
-  if (!ExtensionsDelegate::Get(browser_context_)->UnloadApp(app_id_)) {
-    while(!activity_list_.empty())
-      Activity::Delete(activity_list_.back());
-  }
+  // Unload the application asynchronously to avoid the activity destruction
+  // while we are in an observerloop.

[sadrul, 2014/09/12 16:30:14]

I am not sure what this means, but if you mean while iterating over
ObserverList, then that should be fine (i.e. you can add/remove observers from
the ObserverList you are iterating over).

[Mr4D (OOO till 08-26), 2014/09/12 20:11:26]

Updated the comment.

But I do not remember exactly how I did get into this situation. (I think it was
a special case where the last item got erased) I will have another look into
this and let you know, but first lets land this patch (there is already far too
much addressed which is far from ideal).

+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE,
+      base::Bind(&AppActivityRegistry::DelayedUnload, base::Unretained(this)));
 }
 
 void AppActivityRegistry::ProxyDestroyed(AppActivityProxy* proxy) {
   DCHECK_EQ(unloaded_activity_proxy_, proxy);
   unloaded_activity_proxy_ = NULL;
   if (activity_list_.empty()) {
     AppRegistry::Get()->RemoveAppActivityRegistry(this);
     // |This| is gone now.
   }
 }
 
 void AppActivityRegistry::RestartApplication(AppActivityProxy* proxy) {
   DCHECK_EQ(unloaded_activity_proxy_, proxy);
   // Restart the application. Note that the first created app window will make
   // sure that the proxy gets deleted - after - the new activity got moved
   // to the proxies activity location.
   ExtensionsDelegate::Get(browser_context_)->LaunchApp(app_id_);
 }
 
+void AppActivityRegistry::DelayedUnload() {
+  if (!ExtensionsDelegate::Get(browser_context_)->UnloadApp(app_id_)) {
+    while(!activity_list_.empty())
+      Activity::Delete(activity_list_.back());
+  }
+}
+
 AppActivity* AppActivityRegistry::GetMruActivity() {
   DCHECK(activity_list_.size());
   WindowListProvider* window_list_provider =
       WindowManager::GetInstance()->GetWindowListProvider();
   const aura::Window::Windows children =
       window_list_provider->GetWindowList();
   // Find the first window in the container which is part of the application.
   for (aura::Window::Windows::const_iterator child_iterator = children.begin();
       child_iterator != children.end(); ++child_iterator) {
     for (std::vector<AppActivity*>::iterator app_iterator =
              activity_list_.begin();
          app_iterator != activity_list_.end(); ++app_iterator) {
       if (*child_iterator == (*app_iterator)->GetWindow())
         return *app_iterator;
     }
   }
   NOTREACHED() << "The application does not get tracked by the mru list";
   return NULL;
 }
 
 }  // namespace athena