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
void SBEntry::SetPrefixAt(int index, const SBPrefix& prefix) {
  DCHECK(IsPrefix());

  if (IsAdd())
    add_prefixes_[index] = prefix;
  else
    sub_prefixes_[index].prefix = prefix;
}

void SBEntry::SetPrefixAt(int index, const SBPrefix& prefix) {
  DCHECK(IsPrefix());

  if (IsAdd())
    add_prefixes_[index] = prefix;
  else
    sub_prefixes_[index].prefix = prefix;
}
