Remove remaining dependency on test_runner from components.

components/test_runner/test_common.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_TEST_RUNNER_TEST_COMMON_H_
 #define COMPONENTS_TEST_RUNNER_TEST_COMMON_H_
 
 #include <string>
 
 #include "base/strings/string_util.h"
@@ skipping 15 matching lines @@
 }
 
 TEST_RUNNER_EXPORT std::string NormalizeLayoutTestURL(const std::string& url);
 
 std::string URLDescription(const GURL& url);
 const char* WebNavigationPolicyToString(
     const blink::WebNavigationPolicy& policy);
 
 blink::WebString V8StringToWebString(v8::Local<v8::String> v8_str);
 
-// Tests which depend on Blink must call this function on the main thread
-// before creating/calling any Blink objects/APIs.
-TEST_RUNNER_EXPORT void EnsureBlinkInitialized();
-
 }  // namespace test_runner
 
 #endif  // COMPONENTS_TEST_RUNNER_TEST_COMMON_H_