Add a new entry point for making promise images

This paves the way for promise image sharing among direct & recording
contexts, and untethers promise images from DDL recorder.

Followup CLs will migrate us to actually use this entry point,
and then migrate Chrome to do same.

Bug: skia:10286
Change-Id: I0ad46e8e4b91d8bc03cb039b304d2ea6d8a65c35
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/373716
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/GrDrawingManager.cpp b/src/gpu/GrDrawingManager.cpp
index bd3ae75..2b48ba2 100644
--- a/src/gpu/GrDrawingManager.cpp
+++ b/src/gpu/GrDrawingManager.cpp
@@ -609,7 +609,7 @@
     SkDEBUGCODE(this->validate());
 
     if (fActiveOpsTask) {
-        // This is  a temporary fix for the partial-MDB world. In that world we're not
+        // This is a temporary fix for the partial-MDB world. In that world we're not
         // reordering so ops that (in the single opsTask world) would've just glommed onto the
         // end of the single opsTask but referred to a far earlier RT need to appear in their
         // own opsTask.