Allow setContentDecryptionModule() to get called when setting is done.

media/base/test_helpers.h

 // Copyright (c) 2012 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_TEST_HELPERS_H_
 #define MEDIA_BASE_TEST_HELPERS_H_
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "media/base/channel_layout.h"
@@ skipping 107 matching lines @@
 // some sanity check.
 scoped_refptr<DecoderBuffer> CreateFakeVideoBufferForTest(
     const VideoDecoderConfig& config,
     base::TimeDelta timestamp,
     base::TimeDelta duration);
 
 // Verify if a fake video DecoderBuffer is valid.
 bool VerifyFakeVideoBufferForTest(const scoped_refptr<DecoderBuffer>& buffer,
                                   const VideoDecoderConfig& config);
 
+// Used to verify that the number of calls to A() match the number of calls to

[xhwang, 2014/08/09 00:56:03]

We are not tracking "the number of calls" since we use a boolean. Need to update
to match exactly what we are doing.

[jrummell, 2014/08/11 21:47:15]

Done.

+// B() and that the calls happen in pairs (e.g. B() called after every A()
+// call). There may be any number of pairs (including 0).
+class MatchingCallbackVerifier {

[xhwang, 2014/08/09 00:56:03]

Naming bikeshedding.. In our use case, this is really checking all registered
callbacks are canceled. Can we do

s/MatchingCallbackVerifier/CallbackCancellationChecker
s/RecordACalled/RegisterCallback
s/RecordBCalled/CancelCallback

If we want to make this generic in the sense that it tracks a pair of calls,
then it should be something like CallbackPairChecker...

[jrummell, 2014/08/11 21:47:15]

Like CallbackPairChecker.

+ public:
+  MatchingCallbackVerifier();
+  ~MatchingCallbackVerifier();
+  void RecordACalled();
+  void RecordBCalled();
+
+ private:
+  bool expecting_b_;
+};
+
 }  // namespace media
 
 #endif  // MEDIA_BASE_TEST_HELPERS_H_