tests: Use runPendingTasks instead of WebThread::enterRunLoop()/exitRunLoop()

Source/core/fetch/MemoryCacheTest.cpp

Index: Source/core/fetch/MemoryCacheTest.cpp
diff --git a/Source/core/fetch/MemoryCacheTest.cpp b/Source/core/fetch/MemoryCacheTest.cpp
index 9f9e4e063978b3dd6fde5335f9f95de46aeb0214..abae5649c2d0cb580295d9c06aba74814526eea5 100644
--- a/Source/core/fetch/MemoryCacheTest.cpp
+++ b/Source/core/fetch/MemoryCacheTest.cpp
@@ -34,6 +34,7 @@
 #include "core/fetch/MockImageResourceClient.h"
 #include "core/fetch/RawResource.h"
 #include "core/fetch/ResourcePtr.h"
+#include "core/testing/UnitTestHelpers.h"
 #include "platform/network/ResourceRequest.h"
 #include "public/platform/Platform.h"
 #include "wtf/OwnPtr.h"
@@ -249,7 +250,6 @@ static void TestLiveResourceEvictionAtEndOfTask(Resource* cachedDeadResource, co
             // Next task: now, the live resource was evicted.
             ASSERT_EQ(0u, memoryCache()->deadSize());
             ASSERT_EQ(m_liveSizeWithoutDecode, memoryCache()->liveSize());
-            blink::Platform::current()->currentThread()->exitRunLoop();
         }
 
     private:
@@ -259,7 +259,7 @@ static void TestLiveResourceEvictionAtEndOfTask(Resource* cachedDeadResource, co
 
     blink::Platform::current()->currentThread()->postTask(FROM_HERE, new Task1(cachedLiveResource, cachedDeadResource));
     blink::Platform::current()->currentThread()->postTask(FROM_HERE, new Task2(cachedLiveResource->encodedSize() + cachedLiveResource->overheadSize()));
-    blink::Platform::current()->currentThread()->enterRunLoop();
+    testing::runPendingTasks();
     cachedLiveResource->removeClient(&client);
 }