Fix some leaks and failures under valgrind in JS extensions unit tests.

extensions/renderer/api_test_base.h

Index: extensions/renderer/api_test_base.h
diff --git a/extensions/renderer/api_test_base.h b/extensions/renderer/api_test_base.h
index 4d74995b7111c0e1ac5f91d631cc222ce3e29d45..b3e4e87582a68da114b180f6c0fd96207758d0d8 100644
--- a/extensions/renderer/api_test_base.h
+++ b/extensions/renderer/api_test_base.h
@@ -74,6 +74,7 @@ class ApiTestBase : public ModuleSystemTest {
   ApiTestBase();
   virtual ~ApiTestBase();
   virtual void SetUp() OVERRIDE;
+  virtual void TearDown() OVERRIDE;
   void RunTest(const std::string& file_name, const std::string& test_name);
   TestServiceProvider* service_provider() { return service_provider_; }