Add support for the "uploadrequired" attribute for Autofill query responses

BUG=84693
TEST=unit_tests --gtest_filter=AutofillDownloadTest.QueryAndUploadTest

Review URL: http://codereview.chromium.org/6969090

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@87729 0039d316-1c4b-4281-b951-d872f2087c98
void AutofillDownloadManager::SetNegativeUploadRate(double rate) {
  if (rate == negative_upload_rate_)
    return;
  negative_upload_rate_ = rate;
  DCHECK_GE(rate, 0.0);
  DCHECK_LE(rate, 1.0);
  DCHECK(profile_);
  PrefService* preferences = profile_->GetPrefs();
  preferences->SetDouble(prefs::kAutofillNegativeUploadRate, rate);
}

void AutofillDownloadManager::SetNegativeUploadRate(double rate) {
  if (rate == negative_upload_rate_)
    return;
  negative_upload_rate_ = rate;
  DCHECK_GE(rate, 0.0);
  DCHECK_LE(rate, 1.0);
  DCHECK(profile_);
  PrefService* preferences = profile_->GetPrefs();
  preferences->SetDouble(prefs::kAutofillNegativeUploadRate, rate);
}
