Bug 1364922 - Add a new op OpAddExternalVideoImage for multiple-channel video image. r=nical

MozReview-Commit-ID: 3GV4qBfelr5

gfx/layers/ipc/WebRenderMessages.ipdlh

@@ -31,6 +31,11 @@ struct OpAddExternalImage {
   ImageKey key;
 };
 
+struct OpAddExternalVideoImage {
+  ExternalImageId externalImageId;
+  ImageKey[] keys;
+};
+
 struct OpAddCompositorAnimations {
   CompositorAnimations data;
   OptionalTransform transform;
@@ -39,6 +44,7 @@ struct OpAddCompositorAnimations {
 
 union WebRenderParentCommand {
   OpAddExternalImage;
+  OpAddExternalVideoImage;
   CompositableOperation;
   OpAddCompositorAnimations;
 };