Use URLFetcher::Create instead of new in http_bridge.cc.

 This change modified http_bridge so that it uses a factory to construct
the URLFetcher. Moreover, it modified sync_backend_host_unittest.cc to
use an URLFetcher factory which will prevent access to www.example.com during
the test.

BUG=none
TEST=sync_backend_host_unittest.cc

Review URL: http://codereview.chromium.org/7053011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@87227 0039d316-1c4b-4281-b951-d872f2087c98
void LiveSyncTest::SetUpTestServerIfRequired() {
  if (server_type_ == LOCAL_PYTHON_SERVER) {
    if (!SetUpLocalPythonTestServer())
      LOG(FATAL) << "Failed to set up local python test server";
  } else if (server_type_ == LOCAL_LIVE_SERVER) {
    if (!SetUpLocalTestServer())
      LOG(FATAL) << "Failed to set up local test server";
  } else if (server_type_ == EXTERNAL_LIVE_SERVER) {
  } else {
    LOG(FATAL) << "Don't know which server environment to run test in.";
  }
}

void LiveSyncTest::SetUpTestServerIfRequired() {
  if (server_type_ == LOCAL_PYTHON_SERVER) {
    if (!SetUpLocalPythonTestServer())
      LOG(FATAL) << "Failed to set up local python test server";
  } else if (server_type_ == LOCAL_LIVE_SERVER) {
    if (!SetUpLocalTestServer())
      LOG(FATAL) << "Failed to set up local test server";
  } else if (server_type_ == EXTERNAL_LIVE_SERVER) {
  } else {
    LOG(FATAL) << "Don't know which server environment to run test in.";
  }
}
