Implement disabling and enabling media tracks

media/test/pipeline_integration_test_base.h

Index: media/test/pipeline_integration_test_base.h
diff --git a/media/test/pipeline_integration_test_base.h b/media/test/pipeline_integration_test_base.h
index c3f8bca9a5f60fafa955df9072a996a490bce347..0aacf2c94baef888afbf88c0bba1ef12cb64f43d 100644
--- a/media/test/pipeline_integration_test_base.h
+++ b/media/test/pipeline_integration_test_base.h
@@ -109,6 +109,10 @@ class PipelineIntegrationTestBase : public Pipeline::Client {
   // enabled.
   std::string GetAudioHash();
 
+  // Reset video hash to restart hashing from scratch (e.g. after a seek or
+  // after disabling a media track).
+  void ResetVideoHash();
+
   // Returns the time taken to render the complete audio file.
   // Pipeline must have been started with clockless playback enabled.
   base::TimeDelta GetAudioTime();