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

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

 // 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.
 
 #include "platform/scheduler/renderer/web_frame_scheduler_impl.h"
 
 #include <memory>
 
 #include "base/callback.h"
 #include "base/memory/ptr_util.h"
 #include "base/test/simple_test_tick_clock.h"
 #include "cc/test/ordered_simple_task_runner.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/WebTaskRunner.h"
 #include "platform/scheduler/base/test_time_source.h"
 #include "platform/scheduler/child/scheduler_tqm_delegate_for_test.h"
 #include "platform/scheduler/renderer/renderer_scheduler_impl.h"
 #include "platform/scheduler/renderer/web_view_scheduler_impl.h"
 #include "public/platform/WebTraceLocation.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blink {
 namespace scheduler {
 
-class WebFrameSchedulerImplTest : public testing::Test {
+class WebFrameSchedulerImplTest : public ::testing::Test {
  public:
   WebFrameSchedulerImplTest() {}
   ~WebFrameSchedulerImplTest() override {}
 
   void SetUp() override {
     clock_.reset(new base::SimpleTestTickClock());
     clock_->Advance(base::TimeDelta::FromMicroseconds(5000));
     mock_task_runner_ =
         make_scoped_refptr(new cc::OrderedSimpleTaskRunner(clock_.get(), true));
     delegate_ = SchedulerTqmDelegateForTest::Create(
@@ skipping 238 matching lines @@
 
   // Wait 100 secs virtually and run pending tasks just in case.
   clock_->Advance(base::TimeDelta::FromSeconds(100));
   mock_task_runner_->RunUntilIdle();
 
   observer->CheckObserverState(throttled_count, not_throttled_count);
 }
 
 }  // namespace scheduler
 }  // namespace blink