Coverity: Fixing pass by value.
CID=101462, 101458, 101437, 101471, 101467

BUG=NONE
TEST=NONE

Review URL: http://codereview.chromium.org/9006023

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@115257 0039d316-1c4b-4281-b951-d872f2087c98
void ExtensionPrefs::AcknowledgeExternalExtension(
    const std::string& extension_id) {
  DCHECK(Extension::IdIsValid(extension_id));
  UpdateExtensionPref(extension_id, kPrefExternalAcknowledged,
                      Value::CreateBooleanValue(true));
}

void ExtensionPrefs::AcknowledgeExternalExtension(
    const std::string& extension_id) {
  DCHECK(Extension::IdIsValid(extension_id));
  UpdateExtensionPref(extension_id, kPrefExternalAcknowledged,
                      Value::CreateBooleanValue(true));
}
