This defers starting background extension page RenderViews

chrome/browser/extensions/extension_process_manager.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/browser/extensions/extension_process_manager.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
@@ skipping 286 matching lines @@
   ExtensionHost* host =
 #if defined(OS_MACOSX)
       new extensions::ExtensionHostMac(
           extension, GetSiteInstanceForURL(url), url,
           extensions::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
 #else
       new ExtensionHost(extension, GetSiteInstanceForURL(url), url,
                         extensions::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
 #endif
 
-  host->CreateRenderViewSoon();
+  if (defer_background_host_creation_)

[Matt Perry, 2013/08/31 00:22:23]

Since you're doing this for all background hosts, I think it'd be better to use
ExtensionProcessManager::DeferLoadingBackgroundHosts. Add some logic to call
CreateBackgroundHostsForProfileStartup when that switches from true to false.
Then you don't need to change ExtensionHost at all.

[Greg Spencer (Chromium), 2013/09/03 19:09:31]

Good point, that does simplify things. Done.

+    host->CreateRenderViewDeferred();
+  else
+    host->CreateRenderViewSoon();
   OnExtensionHostCreated(host, true);
 }
 
 ExtensionHost* ExtensionProcessManager::GetBackgroundHostForExtension(
     const std::string& extension_id) {
   for (ExtensionHostSet::iterator iter = background_hosts_.begin();
        iter != background_hosts_.end(); ++iter) {
     ExtensionHost* host = *iter;
     if (host->extension_id() == extension_id)
       return host;
@@ skipping 219 matching lines @@
         new ExtensionMsg_CancelSuspend(extension->id()));
     // This increment / decrement is to simulate an instantaneous event. This
     // has the effect of invalidating close_sequence_id, preventing any in
     // progress closes from completing and starting a new close process if
     // necessary.
     IncrementLazyKeepaliveCount(extension);
     DecrementLazyKeepaliveCount(extension);
   }
 }
 
+void ExtensionProcessManager::DeferBackgroundHostCreation(bool defer) {
+  defer_background_host_creation_ = defer;
+}
+
+void ExtensionProcessManager::CreateDeferredBackgroundHosts() {
+  ExtensionHost::CreateDeferredRenderViews();
+}
+
 void ExtensionProcessManager::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
   switch (type) {
     case chrome::NOTIFICATION_BROWSER_WINDOW_READY: {
       // If a window for this profile, or this profile's incognito profile,
       // has been opened, make sure this profile's background hosts have
       // been loaded.
       Browser* browser = content::Source<Browser>(source).ptr();
@@ skipping 336 matching lines @@
         if (service && service->is_ready())
           CreateBackgroundHostsForProfileStartup();
       }
       break;
     }
     default:
       ExtensionProcessManager::Observe(type, source, details);
       break;
   }
 }