[filemanager] Fix CSP for images: allow icons from other extensions.

BUG=none
TEST=Icons in external actions should be visible.

Review URL: http://codereview.chromium.org/10091040

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@132579 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/file_manager/manifest.json

@@ -22,7 +22,7 @@
     "clipboardRead",
     "https://*.googleusercontent.com/"
   ],
-  "content_security_policy": "default-src 'none'; script-src 'self'; style-src 'self' 'unsafe-inline'; frame-src 'self' about:; img-src 'self' data: filesystem: https://*.googleusercontent.com; media-src filesystem: https://*.googleusercontent.com;",
+  "content_security_policy": "default-src 'none'; script-src 'self'; style-src 'self' 'unsafe-inline'; frame-src 'self' about:; img-src 'self' data: filesystem: https://*.googleusercontent.com chrome://extension-icon; media-src filesystem: https://*.googleusercontent.com;",
   "app": {
     "launch": {
       "local_path": "main.html"