Introduce runtime.onSuspendCanceled() event.

chrome/browser/extensions/extension_process_manager.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 "base/bind.h"
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/string_number_conversions.h"
@@ skipping 94 matching lines @@
 
 struct ExtensionProcessManager::BackgroundPageData {
   // The count of things keeping the lazy background page alive.
   int lazy_keepalive_count;
 
   // This is used with the ShouldUnload message, to ensure that the extension
   // remained idle between sending the message and receiving the ack.
   int close_sequence_id;
 
   // True if the page responded to the ShouldUnload message and is currently
-  // dispatching the unload event. We use this to ignore any activity
-  // generated during the unload event that would otherwise keep the
-  // extension alive.
+  // dispatching the unload event. During this time any events that arrive will
+  // cancel the unload process and an onSuspendCanceled event will be dispatched
+  // to the page.
   bool is_closing;
 
   // Keeps track of when this page was last unloaded. Used for perf metrics.
   linked_ptr<PerfTimer> since_unloaded;
 
   BackgroundPageData()
       : lazy_keepalive_count(0), close_sequence_id(0), is_closing(false) {}
 };
 
 //
@@ skipping 296 matching lines @@
   return count;
 }
 
 int ExtensionProcessManager::DecrementLazyKeepaliveCount(
      const Extension* extension) {
   if (!extension->has_lazy_background_page())
     return 0;
 
   int& count = background_page_data_[extension->id()].lazy_keepalive_count;
   DCHECK_GT(count, 0);
-  if (--count == 0) {
-    MessageLoop::current()->PostDelayedTask(
-        FROM_HERE,
-        base::Bind(&ExtensionProcessManager::OnLazyBackgroundPageIdle,
-                   weak_ptr_factory_.GetWeakPtr(), extension->id(),
-                   ++background_page_data_[extension->id()].close_sequence_id),
-        event_page_idle_time_);
-  }
+  --count;
+  MaybePostOnLazyBackgroundPageIdle(extension->id());
 
   return count;
 }
+
 void ExtensionProcessManager::IncrementLazyKeepaliveCountForView(
     RenderViewHost* render_view_host) {
   WebContents* web_contents =
       WebContents::FromRenderViewHost(render_view_host);
   chrome::ViewType view_type = chrome::GetViewType(web_contents);
   if (view_type != chrome::VIEW_TYPE_INVALID &&
       view_type != chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE) {
     const Extension* extension = GetExtensionForRenderViewHost(
         render_view_host);
     if (extension)
       IncrementLazyKeepaliveCount(extension);
   }
 }
 
+void ExtensionProcessManager::MaybePostOnLazyBackgroundPageIdle(
+    const std::string& extension_id) {
+  if (background_page_data_[extension_id].lazy_keepalive_count == 0) {
+    MessageLoop::current()->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(&ExtensionProcessManager::OnLazyBackgroundPageIdle,
+                    weak_ptr_factory_.GetWeakPtr(), extension_id,
+                    ++background_page_data_[extension_id].close_sequence_id),
+        event_page_idle_time_);
+  }
+}
+
 void ExtensionProcessManager::OnLazyBackgroundPageIdle(
     const std::string& extension_id, int sequence_id) {
   ExtensionHost* host = GetBackgroundHostForExtension(extension_id);
   if (host && !background_page_data_[extension_id].is_closing &&
       sequence_id == background_page_data_[extension_id].close_sequence_id) {
     // Tell the renderer we are about to close. This is a simple ping that the
     // renderer will respond to. The purpose is to control sequencing: if the
     // extension remains idle until the renderer responds with an ACK, then we
     // know that the extension process is ready to shut down. If our
     // close_sequence_id has already changed, then we would ignore the
@@ skipping 16 matching lines @@
 void ExtensionProcessManager::OnShouldUnloadAck(
      const std::string& extension_id, int sequence_id) {
   ExtensionHost* host = GetBackgroundHostForExtension(extension_id);
   if (host &&
       sequence_id == background_page_data_[extension_id].close_sequence_id) {
     host->render_view_host()->Send(new ExtensionMsg_Unload(extension_id));
   }
 }
 
 void ExtensionProcessManager::OnUnloadAck(const std::string& extension_id) {
+  background_page_data_[extension_id].is_closing = true;
+  int sequence_id = background_page_data_[extension_id].close_sequence_id;
   MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ExtensionProcessManager::CloseLazyBackgroundPageNow,
-                 weak_ptr_factory_.GetWeakPtr(), extension_id),
+                 weak_ptr_factory_.GetWeakPtr(), extension_id, sequence_id),
       event_page_unloading_time_);
 }
 
 void ExtensionProcessManager::CloseLazyBackgroundPageNow(
-    const std::string& extension_id) {
-  background_page_data_[extension_id].is_closing = true;
+    const std::string& extension_id, int sequence_id) {
   ExtensionHost* host = GetBackgroundHostForExtension(extension_id);
-  if (host)
-    CloseBackgroundHost(host);
+  if (host &&
+      sequence_id == background_page_data_[extension_id].close_sequence_id) {
+    ExtensionHost* host = GetBackgroundHostForExtension(extension_id);
+    if (host)
+      CloseBackgroundHost(host);
+  }
 }
 
 void ExtensionProcessManager::OnNetworkRequestStarted(
     RenderViewHost* render_view_host) {
   ExtensionHost* host = GetBackgroundHostForExtension(
       GetExtensionID(render_view_host));
   if (host && host->render_view_host() == render_view_host)
     IncrementLazyKeepaliveCount(host->extension());
 }
 
 void ExtensionProcessManager::OnNetworkRequestDone(
     RenderViewHost* render_view_host) {
   ExtensionHost* host = GetBackgroundHostForExtension(
       GetExtensionID(render_view_host));
   if (host && host->render_view_host() == render_view_host)
     DecrementLazyKeepaliveCount(host->extension());
 }
 
+void ExtensionProcessManager::CancelSuspend(const std::string& extension_id) {
+  ExtensionHost* host = GetBackgroundHostForExtension(extension_id);
+  if (host) {
+    bool& is_closing = background_page_data_[extension_id].is_closing;
+    if (is_closing) {
+      host->render_view_host()->Send(
+          new ExtensionMsg_CancelUnload(extension_id));
+      is_closing = false;
+    }
+  }
+  OnLazyBackgroundPageActive(extension_id);
+  MaybePostOnLazyBackgroundPageIdle(extension_id);
+}
+
 void ExtensionProcessManager::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
   switch (type) {
     case chrome::NOTIFICATION_EXTENSIONS_READY: {
       CreateBackgroundHostsForProfileStartup(this,
           content::Source<Profile>(source).ptr()->
               GetExtensionService()->extensions());
       break;
@@ skipping 243 matching lines @@
         if (service && service->is_ready())
           CreateBackgroundHostsForProfileStartup(this, service->extensions());
       }
       break;
     }
     default:
       ExtensionProcessManager::Observe(type, source, details);
       break;
   }
 }