Disable extensions besides externally installed ones and themes.

chrome/browser/renderer_host/browser_render_process_host.cc

 // Copyright (c) 2006-2009 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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "chrome/browser/renderer_host/browser_render_process_host.h"
 
 #include "build/build_config.h"
@@ skipping 12 matching lines @@
 #include "base/process_util.h"
 #include "base/rand_util.h"
 #include "base/scoped_ptr.h"
 #include "base/shared_memory.h"
 #include "base/singleton.h"
 #include "base/string_util.h"
 #include "base/thread.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/child_process_security_policy.h"
 #include "chrome/browser/extensions/extension_message_service.h"
+#include "chrome/browser/extensions/extensions_service.h"
 #include "chrome/browser/extensions/user_script_master.h"
 #include "chrome/browser/history/history.h"
 #include "chrome/browser/plugin_service.h"
 #include "chrome/browser/profile.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/renderer_host/render_widget_helper.h"
 #include "chrome/browser/renderer_host/render_widget_host.h"
 #include "chrome/browser/renderer_host/resource_message_filter.h"
 #include "chrome/browser/renderer_host/web_cache_manager.h"
 #include "chrome/browser/visitedlink_master.h"
@@ skipping 223 matching lines @@
     switches::kDebugPrint,
     switches::kAllowAllActiveX,
     switches::kMemoryProfiling,
     switches::kEnableWatchdog,
     switches::kMessageLoopHistogrammer,
     switches::kEnableDCHECK,
     switches::kSilentDumpOnDCHECK,
     switches::kUseLowFragHeapCrt,
     switches::kEnableWebWorkers,
     switches::kEnableStatsTable,
-    switches::kEnableExtensions,
     switches::kDisableOutOfProcessDevTools,
     switches::kAutoSpellCorrect,
     switches::kDisableAudio,
     switches::kSimpleDataSource,
     switches::kEnableBenchmarking,
   };
 
   for (size_t i = 0; i < arraysize(switch_names); ++i) {
     if (browser_command_line.HasSwitch(switch_names[i])) {
       cmd_line.AppendSwitchWithValue(switch_names[i],
           browser_command_line.GetSwitchValue(switch_names[i]));
     }
   }
 
+  // Tell the renderer to enable extensions if there are any extensions loaded.
+  //
+  // NOTE: This is subtly different than just passing along whether
+  // --enable-extenisons is present in the browser process. For example, there
+  // is also an extensions.enabled preference, and there may be various special
+  // cases about whether to allow extensions to load. 
+  //
+  // This introduces a race condition where the first renderer never gets
+  // extensions enabled, so we also set the flag if extensions_enabled(). This
+  // isn't perfect though, because of the special cases above.
+  //
+  // TODO(aa): We need to get rid of the need to pass this flag at all. It is
+  // only used in one place in the renderer.
+  if (profile()->GetExtensionsService()) {
+    if (profile()->GetExtensionsService()->extensions()->size() > 0 ||
+        profile()->GetExtensionsService()->extensions_enabled())
+      cmd_line.AppendSwitch(switches::kEnableExtensions);
+  }
+
   // Pass on the browser locale.
   const std::wstring locale = g_browser_process->GetApplicationLocale();
   cmd_line.AppendSwitchWithValue(switches::kLang, locale);
 
   // If we run a FieldTrial that we want to pass to the renderer, this is where
   // the SINGULAR trial name and value should be specified.  Note that only one
   // such flag should be passed/set in the renderer command line.
 
   // Today we're watching the impact of DNS on some page load times.
   FieldTrial* field_trial = FieldTrialList::Find("DnsImpact");
@@ skipping 560 matching lines @@
   ExtensionMessageService* ems = ExtensionMessageService::GetInstance(context);
   ems->AddEventListener(event_name, pid());
 }
 
 void BrowserRenderProcessHost::OnExtensionRemoveListener(
     const std::string& event_name) {
   URLRequestContext* context = profile()->GetRequestContext();
   ExtensionMessageService* ems = ExtensionMessageService::GetInstance(context);
   ems->RemoveEventListener(event_name, pid());
 }