Have GetKeyIds() return the key IDs from the first matching 'pssh' box

media/cdm/cenc_utils.h

Index: media/cdm/cenc_utils.h
diff --git a/media/cdm/cenc_utils.h b/media/cdm/cenc_utils.h
index 8938fb92582a6d387db5dae73f99a9e2de4c33c2..f635a325ea63ffa54cd1abc019cc468eee705135 100644
--- a/media/cdm/cenc_utils.h
+++ b/media/cdm/cenc_utils.h
@@ -17,14 +17,18 @@ namespace media {
 // match. Returns true if |input| looks valid, false otherwise.
 MEDIA_EXPORT bool ValidatePsshInput(const std::vector<uint8_t>& input);
 
-// Gets the Key Ids from a 'pssh' box for the Common SystemID among one or
-// more concatenated 'pssh' boxes. If |input| looks valid, then true is
-// returned and |key_ids| is updated to contain the values found. Otherwise
-// return false.
-MEDIA_EXPORT bool GetKeyIdsForCommonSystemId(const std::vector<uint8_t>& input,
-                                             KeyIdList* key_ids);
-
-// Gets the data field from the first 'pssh' box containing |system_id| UUID.
+// Gets the Key Ids from the first 'pssh' box containing |system_id| among one
+// or more concatenated 'pssh' boxes. Returns true if such a box is found and

[ddorwin, 2015/06/25 21:18:12]

"such" is ambiguous, especially as it relates to v0 boxes. Also, will boxes
without key IDs be skipped until one for the system that has key IDs is found?
#1 below would seem to indicate no. That's fine, but we should be clear.

Depending on the desired behavior, this comment should be updated.

[jrummell, 2015/06/25 22:35:59]

Done.

+// it contains 1 or more key IDs. Returns false otherwise.
+// Notes:
+// 1. If multiple PSSH boxes are found, the "KIDs" of the first matching 'pssh'
+//    box will be set in |key_ids|.
+// 2. Only PSSH boxes are allowed in |input|.

[ddorwin, 2015/06/25 21:18:12]

Will boxes after a supported box still cause an error? (I'm not sure how to best
document the answer.)

[jrummell, 2015/06/25 22:35:58]

Updated comment.

+MEDIA_EXPORT bool GetKeyIds(const std::vector<uint8_t>& input,

[ddorwin, 2015/06/25 21:18:12]

s/input/pssh_boxes/?

[ddorwin, 2015/06/25 21:18:12]

GetKeyIdsFromPsshBoxes

(There is no context at the call site, as in the previous non-CENC-specific
file.)

[jrummell, 2015/06/25 22:35:58]

Done.

[jrummell, 2015/06/25 22:35:59]

Done.

+                            const std::vector<uint8_t>& system_id,
+                            KeyIdList* key_ids);
+
+// Gets the data field from the first 'pssh' box containing |system_id|.
 // Returns true if such a box is found and successfully parsed. Returns false
 // otherwise.
 // Notes: