Be explicit about namespace testing to not mix it with blink::testing

third_party/WebKit/Source/platform/testing/CompositorTest.h

 // Copyright 2016 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 CompositorTest_h
 #define CompositorTest_h
 
 #include "base/memory/ref_counted.h"
 #include "base/test/test_mock_time_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "platform/wtf/Noncopyable.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blink {
 
-class CompositorTest : public testing::Test {
+class CompositorTest : public ::testing::Test {
   WTF_MAKE_NONCOPYABLE(CompositorTest);
 
  public:
   CompositorTest();
   virtual ~CompositorTest();
 
  protected:
   // Mock task runner is initialized here because tests create
   // WebLayerTreeViewImplForTesting which needs the current task runner handle.
   scoped_refptr<base::TestMockTimeTaskRunner> runner_;
   base::ThreadTaskRunnerHandle runner_handle_;
 };
 
 }  // namespace blink
 
 #endif  // CompositorTest_h