Refactor TimeBase to post tasks. Workers to use real Idle tasks.

Source/core/fetch/CachingCorrectnessTest.cpp

 /*
  * Copyright (c) 2014, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 106 matching lines @@
         FetchRequest fetchRequest(ResourceRequest(KURL(ParsedURLString, kResourceURL)), FetchInitiatorInfo());
         return m_fetcher->fetchImage(fetchRequest);
     }
 
     ResourceFetcher* fetcher() const { return m_fetcher.get(); }
 
 private:
     // A simple platform that mocks out the clock, for cache freshness testing.
     class ProxyPlatform : public blink::Platform {
     public:
-        ProxyPlatform() : m_elapsedSeconds(0.) { }
+        ProxyPlatform() : m_oldPlatform(blink::Platform::current()), m_elapsedSeconds(0.) { }
 
         void advanceClock(double seconds)
         {
             m_elapsedSeconds += seconds;
         }
 
     private:
         // From blink::Platform:
         virtual double currentTime()
         {
             return kOriginalRequestDateAsDouble + m_elapsedSeconds;
         }
 
         // These blink::Platform methods must be overriden to make a usable object.
         virtual void cryptographicallyRandomValues(unsigned char* buffer, size_t length) { ASSERT_NOT_REACHED(); }
         virtual const unsigned char* getTraceCategoryEnabledFlag(const char* categoryName)
         {
             return &kAConstUnsignedCharZero;
         }
 
+        WebThread* currentThread() override
+        {
+            return m_oldPlatform->currentThread();
+        }
+
+        blink::Platform* m_oldPlatform; // NOT OWNED
         double m_elapsedSeconds;
     };
 
     virtual void SetUp()
     {
         m_savedPlatform = blink::Platform::current();
         blink::Platform::initialize(&m_proxyPlatform);
 
         // Save the global memory cache to restore it upon teardown.
         m_globalMemoryCache = replaceMemoryCacheForTesting(MemoryCache::create());
@@ skipping 411 matching lines @@
     firstResource->setResponse(fresh200Response);
     memoryCache()->add(firstResource.get());
 
     advanceClock(500.);
 
     ResourcePtr<Resource> fetched = fetch();
     EXPECT_EQ(firstResource, fetched);
 }
 
 } // namespace