Introduce runtime.onSuspendCanceled() event.

chrome/browser/extensions/extension_process_manager.cc

Index: chrome/browser/extensions/extension_process_manager.cc
diff --git a/chrome/browser/extensions/extension_process_manager.cc b/chrome/browser/extensions/extension_process_manager.cc
index ac453d6182d0aec5ae03f332171aeadcec37c91a..0de5da4243f6f88e95b851033719c2a931739df7 100644
--- a/chrome/browser/extensions/extension_process_manager.cc
+++ b/chrome/browser/extensions/extension_process_manager.cc
@@ -112,9 +112,9 @@ struct ExtensionProcessManager::BackgroundPageData {
   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.
@@ -431,17 +431,12 @@ int ExtensionProcessManager::DecrementLazyKeepaliveCount(
 
   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 =
@@ -456,6 +451,18 @@ void ExtensionProcessManager::IncrementLazyKeepaliveCountForView(
   }
 }
 
+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);
@@ -492,19 +499,24 @@ void ExtensionProcessManager::OnShouldUnloadAck(
 }
 
 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(
@@ -523,6 +535,20 @@ void ExtensionProcessManager::OnNetworkRequestDone(
     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,