Only show gray LOADING dialog for Themes.

The patch changes the behavior of the LOADING dialog such that it is only shown for extension downloads from the mini-gallery (theme) url. Note that this means that themes from the chrome extensions gallery will also NOT have the dialog shown.

BUG=29628
TEST=Install an theme from https://tools.google.com/chrome/intl/pt/themes/index.html. The gray LOADING dialog should appear. Install extension or theme from chrome.google.com/extensions. No LOADING dialog should appear

Review URL: http://codereview.chromium.org/507016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@34733 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extensions_service.cc b/chrome/browser/extensions/extensions_service.cc
index 99a97f2a..234638d1 100644
--- a/chrome/browser/extensions/extensions_service.cc
+++ b/chrome/browser/extensions/extensions_service.cc
@@ -101,6 +101,12 @@
   return false;
 }
 
+bool ExtensionsService::IsDownloadFromMiniGallery(const GURL& download_url) {
+  return StartsWithASCII(download_url.spec(),
+                         extension_urls::kMiniGalleryDownloadPrefix,
+                         false);  // case_sensitive
+}
+
 ExtensionsService::ExtensionsService(Profile* profile,
                                      const CommandLine* command_line,
                                      PrefService* prefs,