TestingPlatformSupport: register Platform instance correctly

third_party/WebKit/Source/platform/testing/TestingPlatformSupport.cpp

Index: third_party/WebKit/Source/platform/testing/TestingPlatformSupport.cpp
diff --git a/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.cpp b/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.cpp
index 42251b0e09c04f1f965b6847511014d35819d10c..f05ff238b97a2d8d9de3fb15462bb3840944a08c 100644
--- a/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.cpp
+++ b/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.cpp
@@ -141,12 +141,13 @@ TestingPlatformSupport::TestingPlatformSupport(const Config& config)
     : m_config(config),
       m_oldPlatform(Platform::current()),
       m_interfaceProvider(new TestingInterfaceProvider) {
-  ASSERT(m_oldPlatform);
-  Platform::setCurrentPlatformForTesting(this);
+  DCHECK(m_oldPlatform);
 }
 
 TestingPlatformSupport::~TestingPlatformSupport() {
-  Platform::setCurrentPlatformForTesting(m_oldPlatform);
+  // Checks if Platform::setCurrentPlatformForTesting() was correctly called
+  // after the construction.
+  DCHECK_NE(m_oldPlatform, Platform::current());
 }
 
 WebString TestingPlatformSupport::defaultLocale() {
@@ -332,8 +333,8 @@ ScopedUnittestsEnvironmentSetup::ScopedUnittestsEnvironmentSetup(int argc,
 
   m_compositorSupport = WTF::wrapUnique(new cc_blink::WebCompositorSupportImpl);
   m_testingPlatformConfig.compositorSupport = m_compositorSupport.get();
-  m_testingPlatformSupport =
-      WTF::makeUnique<TestingPlatformSupport>(m_testingPlatformConfig);
+  m_testingPlatformSupport.reset(
+      WTF::makeUnique<TestingPlatformSupport>(m_testingPlatformConfig));
 
   ProcessHeap::init();
   ThreadState::attachMainThread();