Revert changes to have ExtensionService notify ThemeService directly

chrome/browser/extensions/extension_install_ui_browsertest.cc

Index: chrome/browser/extensions/extension_install_ui_browsertest.cc
diff --git a/chrome/browser/extensions/extension_install_ui_browsertest.cc b/chrome/browser/extensions/extension_install_ui_browsertest.cc
index 3bd833ecd3404cf0b38890331d9a24cc886eb6c0..66795deafc6d12b0598f6f7ff1a23063cabc507a 100644
--- a/chrome/browser/extensions/extension_install_ui_browsertest.cc
+++ b/chrome/browser/extensions/extension_install_ui_browsertest.cc
@@ -50,12 +50,7 @@ class ExtensionInstallUIBrowserTest : public ExtensionBrowserTest {
   }
 
   const Extension* GetTheme() const {
-    Profile* profile = browser()->profile();
-    std::string theme_id = ThemeService::GetThemeIDForProfile(profile);
-    return
-        (theme_id == ThemeService::kDefaultThemeID) ?
-        NULL :
-        profile->GetExtensionService()->GetExtensionById(theme_id, false);
+    return ThemeServiceFactory::GetThemeForProfile(browser()->profile());
   }
 };