cc: Implement UnionTraits for DrawQuads

cc/ipc/quads.mojom

Index: cc/ipc/quads.mojom
diff --git a/cc/ipc/quads.mojom b/cc/ipc/quads.mojom
index 772525891325f0c5383b46c25f3a047483a19508..c4e15d135a6b9ed6d1d9de2ab793e01ba8938cf7 100644
--- a/cc/ipc/quads.mojom
+++ b/cc/ipc/quads.mojom
@@ -98,9 +98,7 @@ struct YUVVideoQuadState {
 };
 
 enum Material {

[yzshen1, 2016/08/09 18:29:53]

Could we also remove this definition?

[Fady Samuel, 2016/08/09 18:42:50]

Done.

-  INVALID,
   DEBUG_BORDER,
-  PICTURE_CONTENT,
   RENDER_PASS,
   SOLID_COLOR,
   STREAM_VIDEO_CONTENT,
@@ -110,9 +108,18 @@ enum Material {
   YUV_VIDEO_CONTENT,
 };
 
-struct DrawQuad {
-  Material material;
+union DrawQuadState {
+  DebugBorderQuadState debug_border_quad_state;
+  RenderPassQuadState render_pass_quad_state;
+  SolidColorQuadState solid_color_quad_state;
+  SurfaceQuadState surface_quad_state;
+  TextureQuadState texture_quad_state;
+  TileQuadState tile_quad_state;
+  StreamVideoQuadState stream_video_quad_state;
+  YUVVideoQuadState yuv_video_quad_state;
+};
 
+struct DrawQuad {
   // This rect, after applying the quad_transform(), gives the geometry that
   // this quad should draw to. This rect lives in content space.
   gfx.mojom.Rect rect;
@@ -133,13 +140,5 @@ struct DrawQuad {
   // quads.
   SharedQuadState? sqs;
 
-  // Only one of the following will be set, depending on the material.
-  DebugBorderQuadState? debug_border_quad_state;
-  RenderPassQuadState? render_pass_quad_state;
-  SolidColorQuadState? solid_color_quad_state;
-  SurfaceQuadState? surface_quad_state;
-  TextureQuadState? texture_quad_state;
-  TileQuadState? tile_quad_state;
-  StreamVideoQuadState? stream_video_quad_state;
-  YUVVideoQuadState? yuv_video_quad_state;
+  DrawQuadState draw_quad_state;
 };