Implement a module system for the extension bindings JS.

chrome/renderer/extensions/event_bindings.cc

Index: chrome/renderer/extensions/event_bindings.cc
diff --git a/chrome/renderer/extensions/event_bindings.cc b/chrome/renderer/extensions/event_bindings.cc
index 9bab21a945d08f7f2261a6f47c3a2499b18d8a9a..f187f27c5c88cdb9489082dc9d9ddc7130d64fdd 100644
--- a/chrome/renderer/extensions/event_bindings.cc
+++ b/chrome/renderer/extensions/event_bindings.cc
@@ -39,25 +39,26 @@ using content::RenderThread;
 
 namespace {
 
+// A map of event names to the number of contexts listening to that event.
+// We notify the browser about event listeners when we transition between 0
+// and 1.
+typedef std::map<std::string, int> EventListenerCounts;
+
+// A map of extension IDs to listener counts for that extension.
+base::LazyInstance<std::map<std::string, EventListenerCounts> >
+    g_listener_counts = LAZY_INSTANCE_INITIALIZER;
+
+// TODO(koz): Merge this into EventBindings.
 class ExtensionImpl : public ChromeV8Extension {
  public:
+
   explicit ExtensionImpl(ExtensionDispatcher* dispatcher)
-      : ChromeV8Extension("extensions/event.js",
-                          IDR_EVENT_BINDINGS_JS,
-                          dispatcher) {
+      : ChromeV8Extension(dispatcher) {
+    RouteStaticFunction("AttachEvent", &AttachEvent);
+    RouteStaticFunction("DetachEvent", &DetachEvent);
   }
   ~ExtensionImpl() {}
 
-  virtual v8::Handle<v8::FunctionTemplate> GetNativeFunction(
-      v8::Handle<v8::String> name) {
-    if (name->Equals(v8::String::New("AttachEvent"))) {
-      return v8::FunctionTemplate::New(AttachEvent, v8::External::New(this));
-    } else if (name->Equals(v8::String::New("DetachEvent"))) {
-      return v8::FunctionTemplate::New(DetachEvent, v8::External::New(this));
-    }
-    return ChromeV8Extension::GetNativeFunction(name);
-  }
-
   // Attach an event name to an object.
   static v8::Handle<v8::Value> AttachEvent(const v8::Arguments& args) {
     DCHECK(args.Length() == 1);
@@ -76,7 +77,7 @@ class ExtensionImpl : public ChromeV8Extension {
         return v8::Undefined();
 
       EventListenerCounts& listener_counts =
-          self->listener_counts_[context->extension_id()];
+          g_listener_counts.Get()[context->extension_id()];
       if (++listener_counts[event_name] == 1) {
         content::RenderThread::Get()->Send(
             new ExtensionHostMsg_AddListener(context->extension_id(),
@@ -110,7 +111,7 @@ class ExtensionImpl : public ChromeV8Extension {
         return v8::Undefined();
 
       EventListenerCounts& listener_counts =
-          self->listener_counts_[context->extension_id()];
+          g_listener_counts.Get()[context->extension_id()];
       std::string event_name(*v8::String::AsciiValue(args[0]));
       bool is_manual = args[1]->BooleanValue();
 
@@ -135,10 +136,6 @@ class ExtensionImpl : public ChromeV8Extension {
   }
 
  private:
-  // A map of event names to the number of contexts listening to that event.
-  // We notify the browser about event listeners when we transition between 0
-  // and 1.
-  typedef std::map<std::string, int> EventListenerCounts;
 
   bool IsLazyBackgroundPage(const std::string& extension_id) {
     content::RenderView* render_view = GetCurrentRenderView();
@@ -151,14 +148,10 @@ class ExtensionImpl : public ChromeV8Extension {
     return (extension && !extension->background_page_persists() &&
             helper->view_type() == chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
   }
-
-  // A map of extension IDs to listener counts for that extension.
-  std::map<std::string, EventListenerCounts> listener_counts_;
 };
 
 }  // namespace
 
-v8::Extension* EventBindings::Get(ExtensionDispatcher* dispatcher) {
-  static v8::Extension* extension = new ExtensionImpl(dispatcher);
-  return extension;
+ChromeV8Extension* EventBindings::Get(ExtensionDispatcher* dispatcher) {
+  return new ExtensionImpl(dispatcher);
 }