Introduce runtime.onSuspendCanceled() event.

chrome/browser/extensions/lazy_background_task_queue.h

Index: chrome/browser/extensions/lazy_background_task_queue.h
diff --git a/chrome/browser/extensions/lazy_background_task_queue.h b/chrome/browser/extensions/lazy_background_task_queue.h
index 70d1ac0a9c9e1790c949ed1e67cd500b3ce2c421..166bfa5605c4e65547a4e4de48ccd90d599ddcbf 100644
--- a/chrome/browser/extensions/lazy_background_task_queue.h
+++ b/chrome/browser/extensions/lazy_background_task_queue.h
@@ -38,15 +38,15 @@ class LazyBackgroundTaskQueue
   explicit LazyBackgroundTaskQueue(Profile* profile);
   virtual ~LazyBackgroundTaskQueue();
 
-  // Returns true if the task should be added to the queue (that is, if the
-  // extension has a lazy background page that isn't ready yet).
-  bool ShouldEnqueueTask(Profile* profile, const Extension* extension);
-
   // Adds a task to the queue for a given extension. If this is the first
   // task added for the extension, its lazy background page will be loaded.
   // The task will be called either when the page is loaded, or when the
   // page fails to load for some reason (e.g. a crash). In the latter case,
-  // the ExtensionHost parameter is NULL.
+  // the ExtensionHost parameter is NULL. If there is currently a background
+  // page available to handle the task, any suspend the page was in the middle
+  // of will be canceled and the task will be executed with the background page
+  // as an argument. If the extension id isn't lazy, |task| will be executed
+  // straight away.
   void AddPendingTask(
       Profile* profile,
       const std::string& extension_id,
@@ -62,9 +62,20 @@ class LazyBackgroundTaskQueue
                    linked_ptr<PendingTasksList> > PendingTasksMap;
   typedef std::set<PendingTasksKey> PendingPageLoadList;
 
+  // Returns true if the task should be added to the queue (that is, if the
+  // extension has a lazy background page that isn't ready yet).
+  bool ShouldEnqueueTask(Profile* profile, const Extension* extension);
+
   void StartLazyBackgroundPage(Profile* profile,
                                const std::string& extension_id);
 
+  // Executes |task| on an existing ExtensionHost if it exists. If the host is
+  // in the middle of a suspend, that suspend is canceled. Returns true if
+  // |task| was executed.
+  bool ExecuteTaskNowIfPossible(Profile* profile,
+                                const std::string& extension_id,
+                                const PendingTask& task);
+
   // content::NotificationObserver interface.
   virtual void Observe(int type,
                        const content::NotificationSource& source,