Ensure that the last used bookmark folder is actually a folder.

If the user has been creating and deleting bookmarks and bookmark folders
recently, the ID of the last used bookmark folder may actually now correspond to
a bookmark -- not a folder. Detect and correct this situation.

BUG=365933
NOTRY=true

Review URL: https://codereview.chromium.org/247283004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@265820 0039d316-1c4b-4281-b951-d872f2087c98

chrome/android/java/src/org/chromium/chrome/browser/ChromeBrowserProvider.java

@@ -645,7 +645,7 @@ private BookmarkNode getDefaultBookmarkFolder() {
         // then use the synced node (Mobile Bookmarks).
         BookmarkNode lastModified = getBookmarkNode(getLastModifiedBookmarkFolderId(), false, false,
                 false, false);
-        if (lastModified == null) {
+        if (lastModified == null || lastModified.isUrl()) {
             lastModified = getMobileBookmarksFolder();
             mLastModifiedBookmarkFolderId = lastModified != null ? lastModified.id() :
                     INVALID_BOOKMARK_ID;