Protos: Include a discrete MIME type in file_path fields. (#1873)

shared/protos/Background.proto

@@ -25,5 +25,5 @@ message Background {
   optional uint32 width = 15;
   optional uint32 height = 16;
 
-  optional string image = 17 [(gmx) = "data", (file_path) = true];
+  optional string image = 17 [(gmx) = "data", (file_path) = true, (file_kind) = IMAGE];
 }

shared/protos/Sound.proto

@@ -20,7 +20,7 @@ message Sound {
 
   optional Type type = 9 [(gmx) = "types/type"];
 
-  optional string data = 10 [(gmx) = "origname", (file_path) = true];
+  optional string data = 10 [(gmx) = "origname", (file_path) = true, (file_kind) = AUDIO];
 
   optional int32 effects = 11;
   optional uint32 bit_rate = 12 [(gmx) = "bitRates/bitRate"];

shared/protos/Sprite.proto

@@ -35,5 +35,5 @@ message Sprite {
   optional uint32 width = 19;
   optional uint32 height = 20;
 
-  repeated string subimages = 21 [(gmx) = "frames/frame", (file_path) = true];
+  repeated string subimages = 21 [(gmx) = "frames/frame", (file_path) = true, (file_kind) = IMAGE];
 }

shared/protos/options.proto

@@ -1,13 +1,26 @@
-syntax = "proto2";
-package buffers;
-
-import "google/protobuf/descriptor.proto";
-extend google.protobuf.FieldOptions {
-  optional int32 id_start = 50000;
-  optional bool file_path = 50001;
-  optional string resource_ref = 50002;
-  optional string gmx = 50003;
-  optional string gmx_id = 50004;
-  optional string yyp = 50005;
-  optional string yyp_id = 50006;
-}
+syntax = "proto2";
+package buffers;
+
+enum FileKind {
+  UNKNOWN = 0;
+  APPLICATION = 1;
+  AUDIO = 2;
+  FONT = 3;
+  IMAGE = 4;
+  MODEL = 5;
+  TEXT = 6;
+  VIDEO = 7;
+}
+
+import "google/protobuf/descriptor.proto";
+extend google.protobuf.FieldOptions {
+  optional int32 id_start = 50000;
+  optional bool file_path = 50001;
+  optional string resource_ref = 50002;
+  optional string gmx = 50003;
+  optional string gmx_id = 50004;
+  optional string yyp = 50005;
+  optional string yyp_id = 50006;
+  // When file_path is true, this is the type of file indicated.
+  optional FileKind file_kind = 50007;
+}