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

third_party/WebKit/Source/platform/scheduler/renderer/task_cost_estimator_unittest.cc

 // Copyright 2015 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.
 
 #include "platform/scheduler/renderer/task_cost_estimator.h"
 
 #include <memory>
 
 #include "base/test/simple_test_tick_clock.h"
 #include "platform/scheduler/base/test_time_source.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blink {
 namespace scheduler {
 
-class TaskCostEstimatorTest : public testing::Test {
+class TaskCostEstimatorTest : public ::testing::Test {
  public:
   TaskCostEstimatorTest() {}
   ~TaskCostEstimatorTest() override {}
 
   void SetUp() override {
     test_time_source_.reset(new TestTimeSource(&clock_));
   }
 
   base::SimpleTestTickClock clock_;
   std::unique_ptr<TestTimeSource> test_time_source_;
@@ skipping 45 matching lines @@
   estimator.DidProcessTask(task);
   clock_.Advance(base::TimeDelta::FromMilliseconds(500));
   estimator.DidProcessTask(task);
 
   EXPECT_EQ(base::TimeDelta::FromMilliseconds(1000),
             estimator.expected_task_duration());
 }
 
 }  // namespace scheduler
 }  // namespace blink