Unrevert again r119770 - "Event pages: remember events that the page registered for,""

chrome/browser/extensions/extension_event_router.cc

Index: chrome/browser/extensions/extension_event_router.cc
diff --git a/chrome/browser/extensions/extension_event_router.cc b/chrome/browser/extensions/extension_event_router.cc
index 0876aa018e2dc0a9138b4c0bbab59b2df5ad4ede..8d0a8dfb1a1d603441c9f7c229dd9e4eebf34e4a 100644
--- a/chrome/browser/extensions/extension_event_router.cc
+++ b/chrome/browser/extensions/extension_event_router.cc
@@ -23,7 +23,6 @@
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_messages.h"
 #include "chrome/common/extensions/api/extension_api.h"
-#include "content/browser/child_process_security_policy.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_process_host.h"
 
@@ -62,21 +61,18 @@ struct ExtensionEventRouter::EventListener {
 };
 
 struct ExtensionEventRouter::ExtensionEvent {
-  std::string extension_id;
   std::string event_name;
   std::string event_args;
   GURL event_url;
   Profile* restrict_to_profile;
   std::string cross_incognito_args;
 
-  ExtensionEvent(const std::string& extension_id,
-                 const std::string& event_name,
+  ExtensionEvent(const std::string& event_name,
                  const std::string& event_args,
                  const GURL& event_url,
                  Profile* restrict_to_profile,
                  const std::string& cross_incognito_args)
-    : extension_id(extension_id),
-      event_name(event_name),
+    : event_name(event_name),
       event_args(event_args),
       event_url(event_url),
       restrict_to_profile(restrict_to_profile),
@@ -156,6 +152,21 @@ void ExtensionEventRouter::RemoveEventListener(
           profile_, listener.extension_id, event_name));
 }
 
+void ExtensionEventRouter::AddLazyEventListener(
+    const std::string& event_name,
+    const std::string& extension_id) {
+  EventListener lazy_listener(NULL, extension_id);
+  if (lazy_listeners_[event_name].count(lazy_listener) == 0)
+    lazy_listeners_[event_name].insert(lazy_listener);
+}
+
+void ExtensionEventRouter::RemoveLazyEventListener(
+    const std::string& event_name,
+    const std::string& extension_id) {
+  EventListener lazy_listener(NULL, extension_id);
+  lazy_listeners_[event_name].erase(lazy_listener);
+}
+
 bool ExtensionEventRouter::HasEventListener(const std::string& event_name) {
   return (listeners_.find(event_name) != listeners_.end() &&
           !listeners_[event_name].empty());
@@ -182,9 +193,9 @@ void ExtensionEventRouter::DispatchEventToRenderers(
     Profile* restrict_to_profile,
     const GURL& event_url) {
   linked_ptr<ExtensionEvent> event(
-      new ExtensionEvent("", event_name, event_args, event_url,
+      new ExtensionEvent(event_name, event_args, event_url,
                          restrict_to_profile, ""));
-  DispatchEventImpl(event, false);
+  DispatchEventImpl("", event, false);
 }
 
 void ExtensionEventRouter::DispatchEventToExtension(
@@ -195,9 +206,9 @@ void ExtensionEventRouter::DispatchEventToExtension(
     const GURL& event_url) {
   DCHECK(!extension_id.empty());
   linked_ptr<ExtensionEvent> event(
-      new ExtensionEvent(extension_id, event_name, event_args, event_url,
+      new ExtensionEvent(event_name, event_args, event_url,
                          restrict_to_profile, ""));
-  DispatchEventImpl(event, false);
+  DispatchEventImpl(extension_id, event, false);
 }
 
 void ExtensionEventRouter::DispatchEventsToRenderersAcrossIncognito(
@@ -207,24 +218,21 @@ void ExtensionEventRouter::DispatchEventsToRenderersAcrossIncognito(
     const std::string& cross_incognito_args,
     const GURL& event_url) {
   linked_ptr<ExtensionEvent> event(
-      new ExtensionEvent("", event_name, event_args, event_url,
+      new ExtensionEvent(event_name, event_args, event_url,
                          restrict_to_profile, cross_incognito_args));
-  DispatchEventImpl(event, false);
+  DispatchEventImpl("", event, false);
 }
 
-bool ExtensionEventRouter::CanDispatchEventNow(
-    const std::string& extension_id) {
-  if (extension_id.empty())
-    // TODO(mpcomplete): We need to test this per-extension, rather than
-    // globally.
-    return true;
-
-  const Extension* extension = profile_->GetExtensionService()->
-      GetExtensionById(extension_id, false);
-  if (extension && extension->has_background_page() &&
+bool ExtensionEventRouter::CanDispatchEventNow(const Extension* extension) {
+  DCHECK(extension);
+  if (extension->has_background_page() &&
       !extension->background_page_persists()) {
     ExtensionProcessManager* pm = profile_->GetExtensionProcessManager();
-    if (!pm->GetBackgroundHostForExtension(extension_id)) {
+
+    // TODO(mpcomplete): this is incorrect. We need to check whether the page
+    // has finished loading. If not, we can't dispatch the event (because the
+    // listener hasn't been set up yet).
+    if (!pm->GetBackgroundHostForExtension(extension->id())) {
       pm->CreateBackgroundHost(extension, extension->GetBackgroundURL());
       return false;
     }
@@ -234,7 +242,13 @@ bool ExtensionEventRouter::CanDispatchEventNow(
 }
 
 void ExtensionEventRouter::DispatchEventImpl(
-    const linked_ptr<ExtensionEvent>& event, bool was_pending) {
+    const std::string& extension_id,
+    const linked_ptr<ExtensionEvent>& event,
+    bool was_pending) {
+  // Ensure we are only dispatching pending events to a particular extension.
+  if (was_pending)
+    CHECK(!extension_id.empty());
+
   if (!profile_)
     return;
 
@@ -242,15 +256,8 @@ void ExtensionEventRouter::DispatchEventImpl(
   DCHECK(!event->restrict_to_profile ||
          profile_->IsSameProfile(event->restrict_to_profile));
 
-  if (!CanDispatchEventNow(event->extension_id)) {
-    // Events should not be made pending twice. This may happen if the
-    // background page is shutdown before we finish dispatching pending events.
-    CHECK(!was_pending);
-    // TODO(tessamac): make sure Background Page notification doesn't
-    //                 happen before the event is added to the pending list.
-    AppendEvent(event);
-    return;
-  }
+  if (!was_pending)
+    LoadLazyBackgroundPagesForEvent(extension_id, event);
 
   ListenerMap::iterator it = listeners_.find(event->event_name);
   if (it == listeners_.end())
@@ -262,12 +269,11 @@ void ExtensionEventRouter::DispatchEventImpl(
   // Send the event only to renderers that are listening for it.
   for (std::set<EventListener>::iterator listener = listeners.begin();
        listener != listeners.end(); ++listener) {
-    if (!event->extension_id.empty() &&
-        event->extension_id != listener->extension_id)
+    if (!extension_id.empty() && extension_id != listener->extension_id)
       continue;
 
-    const Extension* extension = service->GetExtensionById(
-        listener->extension_id, false);
+    const Extension* extension = service->extensions()->GetByID(
+        listener->extension_id);
 
     // The extension could have been removed, but we do not unregister it until
     // the extension process is unloaded.
@@ -307,6 +313,32 @@ void ExtensionEventRouter::DispatchEventImpl(
   }
 }
 
+void ExtensionEventRouter::LoadLazyBackgroundPagesForEvent(
+    const std::string& extension_id,
+    const linked_ptr<ExtensionEvent>& event) {
+  ExtensionService* service = profile_->GetExtensionService();
+
+  ListenerMap::iterator it = lazy_listeners_.find(event->event_name);
+  if (it == lazy_listeners_.end())
+    return;
+
+  std::set<EventListener>& listeners = it->second;
+  for (std::set<EventListener>::iterator listener = listeners.begin();
+       listener != listeners.end(); ++listener) {
+    if (!extension_id.empty() && extension_id != listener->extension_id)
+      continue;
+
+    const Extension* extension = service->extensions()->GetByID(
+        listener->extension_id);
+
+    if (extension && !CanDispatchEventNow(extension)) {
+      // TODO(mpcomplete): make sure Background Page notification doesn't
+      //                   happen before the event is added to the pending list.
+      AppendEvent(extension->id(), event);
+    }
+  }
+}
+
 void ExtensionEventRouter::IncrementInFlightEvents(const Extension* extension) {
   if (!extension->background_page_persists())
     in_flight_events_[extension->id()]++;
@@ -323,14 +355,13 @@ bool ExtensionEventRouter::HasInFlightEvents(const std::string& extension_id) {
 }
 
 void ExtensionEventRouter::AppendEvent(
+    const std::string& extension_id,
     const linked_ptr<ExtensionEvent>& event) {
   PendingEventsList* events_list = NULL;
-  PendingEventsPerExtMap::iterator it =
-      pending_events_.find(event->extension_id);
+  PendingEventsPerExtMap::iterator it = pending_events_.find(extension_id);
   if (it == pending_events_.end()) {
     events_list = new PendingEventsList();
-    pending_events_[event->extension_id] =
-        linked_ptr<PendingEventsList>(events_list);
+    pending_events_[extension_id] = linked_ptr<PendingEventsList>(events_list);
   } else {
     events_list = it->second.get();
   }
@@ -339,8 +370,8 @@ void ExtensionEventRouter::AppendEvent(
 }
 
 void ExtensionEventRouter::DispatchPendingEvents(
-    const std::string &extension_id) {
-  // Find the list of pending events for this extension.
+    const std::string& extension_id) {
+  CHECK(!extension_id.empty());
   PendingEventsPerExtMap::const_iterator map_it =
       pending_events_.find(extension_id);
   if (map_it == pending_events_.end())
@@ -349,11 +380,14 @@ void ExtensionEventRouter::DispatchPendingEvents(
   PendingEventsList* events_list = map_it->second.get();
   for (PendingEventsList::const_iterator it = events_list->begin();
        it != events_list->end(); ++it)
-    DispatchEventImpl(*it, true);
+    DispatchEventImpl(extension_id, *it, true);
 
-  // Delete list.
   events_list->clear();
   pending_events_.erase(extension_id);
+
+  // Check if the extension is idle, which may be the case if no events were
+  // successfully dispatched.
+  profile_->GetExtensionProcessManager()->OnExtensionIdle(extension_id);
 }
 
 void ExtensionEventRouter::Observe(
@@ -382,9 +416,14 @@ void ExtensionEventRouter::Observe(
       break;
     }
     case chrome::NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING: {
-      // TODO: dispatch events in queue.  ExtensionHost is in the details.
+      // If an on-demand background page finished loading, dispatch queued up
+      // events for it.
       ExtensionHost* eh = content::Details<ExtensionHost>(details).ptr();
-      DispatchPendingEvents(eh->extension_id());
+      if (eh->extension_host_type() ==
+              chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE &&
+          !eh->extension()->background_page_persists()) {
+        DispatchPendingEvents(eh->extension_id());
+      }
       break;
     }
     // TODO(tessamac): if background page crashed/failed clear queue.