Revert the perf-regressing component of r196319.

chrome/renderer/extensions/dispatcher.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/renderer/extensions/dispatcher.h"
 
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/debug/alias.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 1010 matching lines @@
        BackgroundInfo::HasLazyBackgroundPage(extension));
   module_system->RegisterNativeHandler("process",
       scoped_ptr<NativeHandler>(new ProcessInfoNativeHandler(
           this, v8_context, context->GetExtensionID(),
           context->GetContextTypeDescription(),
           ChromeRenderProcessObserver::is_incognito_process(),
           manifest_version, send_request_disabled)));
 
   GetOrCreateChrome(v8_context);
 
-  // TODO(kalman): see comment below about ExtensionAPI.
-  if (extension && !extension->is_platform_app())
-    module_system->Require("miscellaneous_bindings");
-  if (context_type != Feature::WEB_PAGE_CONTEXT)
-    module_system->Require("json");  // see paranoid comment in json.js
+  // Loading JavaScript is expensive, so only run the full API bindings
+  // generation mechanisms in extension pages (NOT all web pages).
+  switch (context_type) {
+    case Feature::UNSPECIFIED_CONTEXT:
+    case Feature::WEB_PAGE_CONTEXT:
+      // TODO(kalman): see comment below about ExtensionAPI.
+      InstallBindings(module_system.get(), v8_context, "app");
+      InstallBindings(module_system.get(), v8_context, "webstore");
+      break;
+    case Feature::BLESSED_EXTENSION_CONTEXT:
+    case Feature::UNBLESSED_EXTENSION_CONTEXT:
+    case Feature::CONTENT_SCRIPT_CONTEXT:
+      if (extension && !extension->is_platform_app())
+        module_system->Require("miscellaneous_bindings");
+      module_system->Require("json");  // see paranoid comment in json.js
 
-  RegisterSchemaGeneratedBindings(module_system.get(), context);
+      // TODO(kalman): move this code back out of the switch and execute it
+      // regardless of |context_type|. ExtensionAPI knows how to return the
+      // correct APIs, however, until it doesn't have a 2MB overhead we can't
+      // load it in every process.
+      RegisterSchemaGeneratedBindings(module_system.get(), context);
+      break;
+  }
 
   bool is_within_platform_app = IsWithinPlatformApp(frame);
   // Inject custom JS into the platform app context.
   if (is_within_platform_app)
     module_system->Require("platformApp");
 
   // Only platform apps support the <webview> tag, because the "webView" and
   // "denyWebView" modules will affect the performance of DOM modifications
   // (http://crbug.com/196453).
   if (context_type == Feature::BLESSED_EXTENSION_CONTEXT &&
@@ skipping 362 matching lines @@
     std::string error_msg = base::StringPrintf(kMessage, function_name.c_str());
     v8::ThrowException(
         v8::Exception::Error(v8::String::New(error_msg.c_str())));
     return false;
   }
 
   return true;
 }
 
 }  // namespace extensions