TestingPlatformSupport: register Platform instance correctly

third_party/WebKit/Source/modules/webaudio/BaseAudioContextTest.cpp

Index: third_party/WebKit/Source/modules/webaudio/BaseAudioContextTest.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/BaseAudioContextTest.cpp b/third_party/WebKit/Source/modules/webaudio/BaseAudioContextTest.cpp
index 0e76d24655733aa96881966f26f2e2020cd091dc..883cab659be6c3a96740116c00107c1235c1d991 100644
--- a/third_party/WebKit/Source/modules/webaudio/BaseAudioContextTest.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/BaseAudioContextTest.cpp
@@ -18,6 +18,7 @@
 #include "platform/testing/TestingPlatformSupport.h"
 #include "public/platform/WebAudioDevice.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "wtf/PtrUtil.h"
 
 namespace blink {
 
@@ -80,6 +81,7 @@ class BaseAudioContextTest : public ::testing::Test {
   using AutoplayStatus = BaseAudioContext::AutoplayStatus;
 
   void SetUp() override {
+    m_testPlatform.reset(WTF::makeUnique<BaseAudioContextTestPlatform>());
     m_dummyPageHolder = DummyPageHolder::create();
     m_dummyFrameOwner = DummyFrameOwner::create();
     document().updateSecurityOrigin(
@@ -124,7 +126,7 @@ class BaseAudioContextTest : public ::testing::Test {
 
   Persistent<LocalFrame> m_childFrame;
 
-  BaseAudioContextTestPlatform m_testPlatform;
+  ScopedTestingPlatformSupport<BaseAudioContextTestPlatform> m_testPlatform;
 };
 
 TEST_F(BaseAudioContextTest, AutoplayMetrics_NoRestriction) {