Make explicit the PipelineStatus enum values and warn that they are logged to UMA.

The explicit values should make it easier to avoid accidentally reusing a
previously-used code as obsolete ones are retired.


Review URL: https://chromiumcodereview.appspot.com/10824283

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151667 0039d316-1c4b-4281-b951-d872f2087c98

media/base/pipeline_status.h

@@ -12,26 +12,27 @@
 namespace media {
 
 // Status states for pipeline.  All codes except PIPELINE_OK indicate errors.
+// Logged to UMA, so never reuse a value, always add new/greater ones!
 // TODO(vrk/scherkus): Trim the unused status codes. (crbug.com/126070)
 enum PipelineStatus {
-  PIPELINE_OK,
-  PIPELINE_ERROR_URL_NOT_FOUND,
-  PIPELINE_ERROR_NETWORK,
-  PIPELINE_ERROR_DECODE,
-  PIPELINE_ERROR_DECRYPT,
-  PIPELINE_ERROR_ABORT,
-  PIPELINE_ERROR_INITIALIZATION_FAILED,
-  PIPELINE_ERROR_REQUIRED_FILTER_MISSING,
-  PIPELINE_ERROR_COULD_NOT_RENDER,
-  PIPELINE_ERROR_READ,
-  PIPELINE_ERROR_OPERATION_PENDING,
-  PIPELINE_ERROR_INVALID_STATE,
+  PIPELINE_OK = 0,
+  PIPELINE_ERROR_URL_NOT_FOUND = 1,
+  PIPELINE_ERROR_NETWORK = 2,
+  PIPELINE_ERROR_DECODE = 3,
+  PIPELINE_ERROR_DECRYPT = 4,
+  PIPELINE_ERROR_ABORT = 5,
+  PIPELINE_ERROR_INITIALIZATION_FAILED = 6,
+  PIPELINE_ERROR_REQUIRED_FILTER_MISSING = 7,
+  PIPELINE_ERROR_COULD_NOT_RENDER = 8,
+  PIPELINE_ERROR_READ = 9,
+  PIPELINE_ERROR_OPERATION_PENDING = 10,
+  PIPELINE_ERROR_INVALID_STATE = 11,
   // Demuxer related errors.
-  DEMUXER_ERROR_COULD_NOT_OPEN,
-  DEMUXER_ERROR_COULD_NOT_PARSE,
-  DEMUXER_ERROR_NO_SUPPORTED_STREAMS,
+  DEMUXER_ERROR_COULD_NOT_OPEN = 12,
+  DEMUXER_ERROR_COULD_NOT_PARSE = 13,
+  DEMUXER_ERROR_NO_SUPPORTED_STREAMS = 14,
   // Decoder related errors.
-  DECODER_ERROR_NOT_SUPPORTED,
+  DECODER_ERROR_NOT_SUPPORTED = 15,
   PIPELINE_STATUS_MAX,  // Must be greater than all other values logged.
 };