Canonicalize the url based on Section 6.1 Safe Browsing Spec.

      BUG=7713
TEST=SafeBrowsingUtilTest.CanonicalizeUrl
Review URL: http://codereview.chromium.org/1275002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@43100 0039d316-1c4b-4281-b951-d872f2087c98