Replace MockFilterCallback with MockCallback and simplify unit tests.

media/base/mock_callback.h

Index: media/base/mock_callback.h
diff --git a/media/base/mock_callback.h b/media/base/mock_callback.h
new file mode 100644
index 0000000000000000000000000000000000000000..5526ee7256cb8af5d07e7a8ee1de3b1a418dc8b7
--- /dev/null
+++ b/media/base/mock_callback.h
@@ -0,0 +1,48 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_BASE_MOCK_CALLBACK_H_
+#define MEDIA_BASE_MOCK_CALLBACK_H_
+
+#include "base/callback.h"
+#include "testing/gmock/include/gmock/gmock.h"
+
+namespace media {
+
+// Helper class used to test that callbacks are executed.
+//
+// In most cases NewExpectedCallback() can be used but if need be you can
+// manually set expectations on an MockCallback object:
+//
+//   StrictMock<MockCallback>* callback =
+//       new StrictMock<MockCallback>();
+//   EXPECT_CALL(*callback, RunWithParams(_));
+//   EXPECT_CALL(*callback, Destructor());
+//
+// ...or if you don't care about verifying callback deletion:
+//
+//   NiceMock<MockCallback>* callback =
+//       new NiceMock<MockCallback>();
+//   EXPECT_CALL(*callback, RunWithParams(_));
+class MockCallback : public CallbackRunner<Tuple0> {
+ public:
+  MockCallback();
+  virtual ~MockCallback();
+
+  MOCK_METHOD1(RunWithParams, void(const Tuple0& params));
+
+  // Can be used to verify the object is destroyed.
+  MOCK_METHOD0(Destructor, void());
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MockCallback);
+};
+
+// Convenience function that automatically creates and sets an expectation for
+// the callback to run.
+MockCallback* NewExpectedCallback();
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_MOCK_CALLBACK_H_