google_apis: Implement more functions in FakeDriveService

chrome/test/data/chromeos/gdata/root_feed.json

 {
    "encoding": "UTF-8",
    "feed": {
       "author": [ {
          "email": {
             "$t": "tester@testing.com"
          },
          "name": {
             "$t": "tester"
          }
@@ skipping 280 matching lines @@
          "category": [ {
             "label": "viewed",
             "scheme": "http://schemas.google.com/g/2005/labels",
             "term": "http://schemas.google.com/g/2005/labels#viewed"
          }, {
             "label": "folder",
             "scheme": "http://schemas.google.com/g/2005#kind",
             "term": "http://schemas.google.com/docs/2007#folder"
          } ],
          "content": {
-            "src": "https://1_folder_content_url",
+            "src": "https://dir_1_self_link/folder:1_folder_resource_id",
             "type": "application/atom+xml;type=feed"
          },
          "docs$writersCanInvite": {
             "value": "true"
          },
          "gd$etag": "\"HhMOFgcNHSt7ImBr\"",
          "gd$feedLink": [ {
             "href": "https://1_folder_feed_linkurl",
             "rel": "http://schemas.google.com/acl/2007#accessControlList"
          } ],
@@ skipping 779 matching lines @@
          "$t": "2011-12-14T01:03:21.151Z"
       },
       "xmlns": "http://www.w3.org/2005/Atom",
       "xmlns$batch": "http://schemas.google.com/gdata/batch",
       "xmlns$docs": "http://schemas.google.com/docs/2007",
       "xmlns$gd": "http://schemas.google.com/g/2005",
       "xmlns$openSearch": "http://a9.com/-/spec/opensearch/1.1/"
    },
    "version": "1.0"
 }