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

third_party/WebKit/Source/platform/scroll/ScrollbarThemeOverlayTest.cpp

 // 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/scroll/ScrollbarThemeOverlay.h"
 
 #include "platform/scroll/ScrollbarTestSuite.h"
 #include "platform/testing/TestingPlatformSupport.h"
 
 namespace blink {
 
-using testing::NiceMock;
-using testing::Return;
+using ::testing::NiceMock;
+using ::testing::Return;
 
-using ScrollbarThemeOverlayTest = testing::Test;
+using ScrollbarThemeOverlayTest = ::testing::Test;
 
 TEST_F(ScrollbarThemeOverlayTest, PaintInvalidation) {
   ScopedTestingPlatformSupport<TestingPlatformSupportWithMockScheduler>
       platform;
 
   NiceMock<MockScrollableArea>* mock_scrollable_area =
       new NiceMock<MockScrollableArea>(ScrollOffset(100, 100));
   ScrollbarThemeOverlay theme(14, 0, ScrollbarThemeOverlay::kAllowHitTest);
 
   Scrollbar* vertical_scrollbar = Scrollbar::CreateForTesting(
@@ skipping 105 matching lines @@
   EXPECT_CALL(*mock_scrollable_area, ScrollbarsHidden())
       .WillOnce(Return(false));
   vertical_scrollbar->SetEnabled(true);
   EXPECT_TRUE(vertical_scrollbar->ThumbNeedsRepaint());
   EXPECT_TRUE(mock_scrollable_area->VerticalScrollbarNeedsPaintInvalidation());
 
   ThreadState::Current()->CollectAllGarbage();
 }
 
 }  // namespace blink