Take extensions out of Profile into a profile-keyed service, ExtensionSystem.

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index dc3625fb5e7f74bf2b5116061df8855f729ebfd0..250ffc533a7f99b145b2a13d253a9806c09098bd 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -28,6 +28,8 @@
 #include "chrome/browser/extensions/extension_info_map.h"
 #include "chrome/browser/extensions/extension_message_handler.h"
 #include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_system.h"
+#include "chrome/browser/extensions/extension_system_factory.h"
 #include "chrome/browser/extensions/extension_web_ui.h"
 #include "chrome/browser/extensions/extension_webkit_preferences.h"
 #include "chrome/browser/geolocation/chrome_access_token_store.h"
@@ -530,7 +532,7 @@ void ChromeContentBrowserClient::SiteInstanceGotProcess(
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&ExtensionInfoMap::RegisterExtensionProcess,
-                 profile->GetExtensionInfoMap(),
+                 ExtensionSystemFactory::GetForProfile(profile)->info_map(),
                  extension->id(),
                  site_instance->GetProcess()->GetID(),
                  site_instance->GetId()));
@@ -559,7 +561,7 @@ void ChromeContentBrowserClient::SiteInstanceDeleting(
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&ExtensionInfoMap::UnregisterExtensionProcess,
-                 profile->GetExtensionInfoMap(),
+                 ExtensionSystemFactory::GetForProfile(profile)->info_map(),
                  extension->id(),
                  site_instance->GetProcess()->GetID(),
                  site_instance->GetId()));