Reland 166821 - Lazy initialization for ProcessesEventRouter.

chrome/browser/extensions/event_router.cc

Index: chrome/browser/extensions/event_router.cc
diff --git a/chrome/browser/extensions/event_router.cc b/chrome/browser/extensions/event_router.cc
index b6683a6f4c5df142df87e9a811be43e2215f674f..19358599082197068e2d0980d61036990b53080b 100644
--- a/chrome/browser/extensions/event_router.cc
+++ b/chrome/browser/extensions/event_router.cc
@@ -13,8 +13,6 @@
 #include "base/values.h"
 #include "base/version.h"
 #include "chrome/browser/browser_process.h"
-#include "chrome/browser/extensions/api/processes/processes_api_constants.h"
-#include "chrome/browser/extensions/api/processes/processes_api.h"
 #include "chrome/browser/extensions/api/runtime/runtime_api.h"
 #include "chrome/browser/extensions/api/web_request/web_request_api.h"
 #include "chrome/browser/extensions/event_names.h"
@@ -122,8 +120,6 @@ void EventRouter::DispatchEvent(IPC::Sender* ipc_sender,
 
 EventRouter::EventRouter(Profile* profile, ExtensionPrefs* extension_prefs)
     : profile_(profile),
-      extension_devtools_manager_(
-          ExtensionSystem::Get(profile)->devtools_manager()),
       listeners_(ALLOW_THIS_IN_INITIALIZER_LIST(this)),
       dispatch_chrome_updated_event_(false) {
   registrar_.Add(this, content::NOTIFICATION_RENDERER_PROCESS_TERMINATED,
@@ -166,23 +162,39 @@ void EventRouter::RemoveEventListener(const std::string& event_name,
   listeners_.RemoveListener(&listener);
 }
 
+void EventRouter::RegisterObserver(Observer* observer,
+                                   const std::string& event_name) {
+  observers_[event_name] = observer;
+}
+
+void EventRouter::UnregisterObserver(Observer* observer) {
+  std::vector<ObserverMap::iterator> iters_to_remove;
+  for (ObserverMap::iterator iter = observers_.begin();
+       iter != observers_.end(); ++iter) {
+    if (iter->second == observer)
+      iters_to_remove.push_back(iter);
+  }
+  for (size_t i = 0; i < iters_to_remove.size(); ++i)
+    observers_.erase(iters_to_remove[i]);
+}
+
 void EventRouter::OnListenerAdded(const EventListener* listener) {
   // We don't care about lazy events being added.
   if (!listener->process)
     return;
 
-  if (extension_devtools_manager_.get())
-    extension_devtools_manager_->AddEventListener(listener->event_name,
-                                                  listener->process->GetID());
-
-  // We lazily tell the TaskManager to start updating when listeners to the
-  // processes.onUpdated or processes.onUpdatedWithMemory events arrive.
   const std::string& event_name = listener->event_name;
-  if (event_name.compare(
-          extensions::processes_api_constants::kOnUpdated) == 0 ||
-      event_name.compare(
-          extensions::processes_api_constants::kOnUpdatedWithMemory) == 0)
-    extensions::ProcessesEventRouter::GetInstance()->ListenerAdded();
+  ObserverMap::iterator observer = observers_.find(event_name);
+  if (observer != observers_.end())
+    observer->second->OnListenerAdded(event_name);
+
+  // TODO(yoz): Migrate these to become EventRouter observers.
+  // EventRouter shouldn't need to know about them.
+  ExtensionDevToolsManager* extension_devtools_manager =
+      ExtensionSystem::Get(profile_)->devtools_manager();
+  if (extension_devtools_manager)
+    extension_devtools_manager->AddEventListener(event_name,
+                                                 listener->process->GetID());
 
   if (SystemInfoEventRouter::IsSystemInfoEvent(event_name))
     SystemInfoEventRouter::GetInstance()->AddEventListener(event_name);
@@ -194,23 +206,22 @@ void EventRouter::OnListenerRemoved(const EventListener* listener) {
     return;
 
   const std::string& event_name = listener->event_name;
-  if (extension_devtools_manager_.get())
-    extension_devtools_manager_->RemoveEventListener(
+  ObserverMap::iterator observer = observers_.find(event_name);
+  if (observer != observers_.end())
+    observer->second->OnListenerRemoved(event_name);
+
+  // TODO(yoz): Migrate these to become EventRouter observers.
+  // EventRouter shouldn't need to know about them.
+  ExtensionDevToolsManager* extension_devtools_manager =
+      ExtensionSystem::Get(profile_)->devtools_manager();
+  if (extension_devtools_manager)
+    extension_devtools_manager->RemoveEventListener(
         event_name, listener->process->GetID());
 
-  // If a processes.onUpdated or processes.onUpdatedWithMemory event listener
-  // is removed (or a process with one exits), then we let the extension API
-  // know that it has one fewer listener.
-  if (event_name.compare(
-          extensions::processes_api_constants::kOnUpdated) == 0 ||
-      event_name.compare(
-          extensions::processes_api_constants::kOnUpdatedWithMemory) == 0)
-    extensions::ProcessesEventRouter::GetInstance()->ListenerRemoved();
-
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&NotifyEventListenerRemovedOnIOThread,
-                 profile_, listener->extension_id, listener->event_name));
+                 profile_, listener->extension_id, event_name));
 
   if (SystemInfoEventRouter::IsSystemInfoEvent(event_name))
     SystemInfoEventRouter::GetInstance()->RemoveEventListener(event_name);