Fix a teardown hang caused by an Abort() call while there is a pending read.

media/base/pipeline_impl.cc

 // Copyright (c) 2010 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.
 //
 // TODO(scherkus): clean up PipelineImpl... too many crazy function names,
 // potential deadlocks, etc...
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/stl_util-inl.h"
@@ skipping 359 matching lines @@
 }
 
 // static
 PipelineImpl::State PipelineImpl::FindNextState(State current) {
   // TODO(scherkus): refactor InitializeTask() to make use of this function.
   if (current == kPausing) {
     return kFlushing;
   } else if (current == kFlushing) {
     // We will always honor Seek() before Stop(). This is based on the
     // assumption that we never accept Seek() after Stop().
-    DCHECK(IsPipelineSeeking() || IsPipelineStopPending());
+    DCHECK(IsPipelineSeeking() ||
+           IsPipelineStopPending() ||
+           IsPipelineTearingDown());
     return IsPipelineSeeking() ? kSeeking : kStopping;
   } else if (current == kSeeking) {
     return kStarting;
   } else if (current == kStarting) {
     return kStarted;
   } else if (current == kStopping) {
     return error_caused_teardown_ ? kError : kStopped;
   } else {
     return current;
   }
@@ skipping 773 matching lines @@
     case kStopping:
     case kStopped:
       NOTREACHED() << "Unexpected state for teardown: " << state_;
       break;
     // default: intentionally left out to force new states to cause compiler
     // errors.
   };
 }
 
 }  // namespace media