Make app_custom_bindings.js lazily evaluated so it doesn't execute on every page load.

chrome/renderer/extensions/extension_dispatcher.cc

Index: chrome/renderer/extensions/extension_dispatcher.cc
diff --git a/chrome/renderer/extensions/extension_dispatcher.cc b/chrome/renderer/extensions/extension_dispatcher.cc
index 1833d64cfa85c23499ccefccec4af4b16bba2fd4..324e93e5c50792370fad2a3bc2d98b07edec22ad 100644
--- a/chrome/renderer/extensions/extension_dispatcher.cc
+++ b/chrome/renderer/extensions/extension_dispatcher.cc
@@ -118,6 +118,24 @@ class PrintNativeHandler : public NativeHandler {
   }
 };
 
+void InstallAppBindings(ModuleSystem* module_system,
+                        v8::Handle<v8::Object> chrome,
+                        v8::Handle<v8::Object> chrome_hidden) {
+  module_system->SetLazyField(chrome, "app", "app", "chromeApp");
+  module_system->SetLazyField(chrome, "appNotifications", "app",
+                              "chromeAppNotifications");
+  module_system->SetLazyField(chrome_hidden, "app", "app",
+                              "chromeHiddenApp");
+}
+
+void InstallWebstoreBindings(ModuleSystem* module_system,
+                             v8::Handle<v8::Object> chrome,
+                             v8::Handle<v8::Object> chrome_hidden) {
+  module_system->SetLazyField(chrome, "webstore", "webstore", "chromeWebstore");
+  module_system->SetLazyField(chrome_hidden, "webstore", "webstore",
+                              "chromeHiddenWebstore");
+}
+
 }
 
 ExtensionDispatcher::ExtensionDispatcher()
@@ -460,6 +478,9 @@ void ExtensionDispatcher::DidCreateScriptContext(
   v8_context_set_.Add(context);
 
   scoped_ptr<ModuleSystem> module_system(new ModuleSystem(&source_map_));
+  // Enable natives in startup.
+  ModuleSystem::NativesEnabledScope natives_enabled_scope(module_system.get());
+
   RegisterNativeHandlers(module_system.get(), context);
 
   module_system->RegisterNativeHandler("chrome_hidden",
@@ -471,6 +492,13 @@ void ExtensionDispatcher::DidCreateScriptContext(
   if (extension)
     manifest_version = extension->manifest_version();
 
+  typedef void (*BindingInstaller)(ModuleSystem* module_system,
+                                  v8::Handle<v8::Object> chrome,
+                                  v8::Handle<v8::Object> chrome_hidden);
+  std::map<std::string, BindingInstaller> lazy_bindings;
+  lazy_bindings["app"] = InstallAppBindings;
+  lazy_bindings["webstore"] = InstallWebstoreBindings;
+
   // Create the 'chrome' variable if it doesn't already exist.
   {
     v8::HandleScope handle_scope;
@@ -513,11 +541,20 @@ void ExtensionDispatcher::DidCreateScriptContext(
 
   for (std::set<std::string>::iterator i = apis->begin(); i != apis->end();
       ++i) {
-    module_system->Require(*i);
+    std::map<std::string, BindingInstaller>::const_iterator lazy_binding =
+        lazy_bindings.find(*i);
+    if (lazy_binding != lazy_bindings.end()) {
+      v8::Handle<v8::Object> global(v8::Context::GetCurrent()->Global());
+      v8::Handle<v8::Object> chrome =
+          global->Get(v8::String::New("chrome"))->ToObject();
+      v8::Handle<v8::Object> chrome_hidden =
+          ChromeV8Context::GetOrCreateChromeHidden(v8_context)->ToObject();
+      (*lazy_binding->second)(module_system.get(), chrome, chrome_hidden);
+    } else {
+      module_system->Require(*i);
+    }
   }
 
-  module_system->set_natives_enabled(false);
-
   context->set_module_system(module_system.Pass());
 
   context->DispatchOnLoadEvent(