Revert of Refactoring: Move some classes from content/child to platform

media/blink/run_all_unittests.cc

Index: media/blink/run_all_unittests.cc
diff --git a/media/blink/run_all_unittests.cc b/media/blink/run_all_unittests.cc
index 8eaac37c8d9bce4b24ac710a5cac1899d598de48..bcbc4e3d315b68ba97faffd62e50e14d8692c622 100644
--- a/media/blink/run_all_unittests.cc
+++ b/media/blink/run_all_unittests.cc
@@ -71,9 +71,6 @@ class TestBlinkPlatformSupport : NON_EXPORTED_BASE(public blink::Platform) {
   ~TestBlinkPlatformSupport() override;
 
   blink::WebThread* currentThread() override { return &m_currentThread; }
-  void registerMemoryDumpProvider(blink::WebMemoryDumpProvider*,
-                                  const char* name) override {}
-  void unregisterMemoryDumpProvider(blink::WebMemoryDumpProvider*) override {}
 
  private:
   CurrentThreadMock m_currentThread;