Add a lot of Pipeline tests to cover stopping/error handling while in a variety of states.

While the use of gmock's InSequence is unfortunate (read: brittle tests), it does help capture the call sequences for various pipeline operations. You may notice in the original incarnation of these tests in http://codereview.chromium.org/10828045/ didn't need InSequence. I'm aiming to remove InSequence after I'm done rewriting the guts of Pipeline.

BUG=110228

Review URL: https://chromiumcodereview.appspot.com/10832197

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@150816 0039d316-1c4b-4281-b951-d872f2087c98

media/base/mock_filters.h

@@ -274,11 +274,6 @@ class MockFilterCollection {
   DISALLOW_COPY_AND_ASSIGN(MockFilterCollection);
 };
 
-// Helper gmock action that calls SetError() on behalf of the provided filter.
-ACTION_P2(SetError, filter, error) {
-  filter->host()->SetError(error);
-}
-
 ACTION(RunClosure) {
   arg0.Run();
 }

media/base/pipeline.cc

@@ -260,6 +260,10 @@ void Pipeline::SetClockForTesting(Clock* clock) {
   clock_.reset(clock);
 }
 
+void Pipeline::SetErrorForTesting(PipelineStatus status) {
+  SetError(status);
+}
+
 void Pipeline::SetState(State next_state) {
   if (state_ != kStarted && next_state == kStarted &&
       !creation_time_.is_null()) {

media/base/pipeline.h

@@ -217,6 +217,7 @@ class MEDIA_EXPORT Pipeline
   PipelineStatistics GetStatistics() const;
 
   void SetClockForTesting(Clock* clock);
+  void SetErrorForTesting(PipelineStatus status);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(PipelineTest, GetBufferedTimeRanges);