MediaError code grouping preliminary design.

This design is still subject to change. We need a way to prevent
collisions in the codes as they get added.

Bug: 1043289
Change-Id: I512b2a66fb0e1f05d56f9910f5dc8c9779112269
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2026411
Commit-Queue: Ted Meyer <tmathmeyer@chromium.org>
Reviewed-by: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#742949}

media/base/media_error_codes.h

@@ -9,14 +9,32 @@ namespace media {
 
 // NOTE: These numbers are still subject to change.  Do not use for things like
 // UMA yet!
+
+// Codes are grouped with a bitmask:
+// 0xFFFFFFFF
+//   └─┬┘├┘└┴ enumeration within the group
+//     │ └─ group code
+//     └─ reserved for now
+// 256 groups is more than anyone will ever need on a computer.
 enum class ErrorCode : uint32_t {
   kOk = 0,
 
-  kCannotMakeContextCurrent = 1000,
-  kCouldNotPostTexture = 1001,
-  kCouldNotPostAcquireStream = 1002,
+  // Decoder Errors: 0x01
+  kDecoderInitializeNeverCompleted = 0x00000101,
+  kDecoderFailedDecode = 0x00000102,
+  kDecoderUnsupportedProfile = 0x00000103,
+  kDecoderUnsupportedCodec = 0x00000104,
+
+  // Windows Errors: 0x02
+  kWindowsWrappedHresult = 0x00000201,
+  kWindowsApiNotAvailible = 0x00000202,
+
+  // D3D11VideoDecoder Errors: 0x03
+  kCannotMakeContextCurrent = 0x00000301,
+  kCouldNotPostTexture = 0x00000302,
+  kCouldNotPostAcquireStream = 0x00000303,
 
-  kCodeOnlyForTesting = 10000,
+  kCodeOnlyForTesting = std::numeric_limits<uint32_t>::max(),
   kMaxValue = kCodeOnlyForTesting,
 };