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

media/base/test_helpers.cc

 // 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.
 
 #include "media/base/test_helpers.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/pickle.h"
@@ skipping 224 matching lines @@
   std::string header;
   int width = 0;
   int height = 0;
   bool success = pickle.ReadString(&header) && pickle.ReadInt(&width) &&
                  pickle.ReadInt(&height);
   return (success && header == kFakeVideoBufferHeader &&
           width == config.coded_size().width() &&
           height == config.coded_size().height());
 }
 
+MatchingCallbackVerifier::MatchingCallbackVerifier() : expecting_B_(false) {
+}
+
+MatchingCallbackVerifier::~MatchingCallbackVerifier() {
+  EXPECT_FALSE(expecting_B_);
+}
+
+void MatchingCallbackVerifier::A() {
+  EXPECT_FALSE(expecting_B_);
+  expecting_B_ = true;
+}
+
+void MatchingCallbackVerifier::B() {
+  EXPECT_TRUE(expecting_B_);
+  expecting_B_ = false;
+}
+
 }  // namespace media