Add a media pipeline status error code for decryption error.

media/base/media_log.cc

Index: media/base/media_log.cc
diff --git a/media/base/media_log.cc b/media/base/media_log.cc
index 0920fb4f4983d4511b50d0c32eb47ee0640cd0f5..d1ac7def7d1c338246f5114182d3c87d77446ded 100644
--- a/media/base/media_log.cc
+++ b/media/base/media_log.cc
@@ -110,6 +110,8 @@ const char* MediaLog::PipelineStatusToString(PipelineStatus status) {
       return "pipeline: network error";
     case PIPELINE_ERROR_DECODE:
       return "pipeline: decode error";
+    case PIPELINE_ERROR_DECRYPT:
+      return "pipeline: decrypt error";
     case PIPELINE_ERROR_ABORT:
       return "pipeline: abort";
     case PIPELINE_ERROR_INITIALIZATION_FAILED: