Add SkSurface flush call that takes a GrBackendSurfaceMutableState.

This new api will eventually replace the version that takes an

SkSurface::BackendAccess.
Change-Id: I48cd013725e14027f386b0b111223459944ac44a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/295567
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
diff --git a/RELEASE_NOTES.txt b/RELEASE_NOTES.txt
index 169b0d5..396d013 100644
--- a/RELEASE_NOTES.txt
+++ b/RELEASE_NOTES.txt
@@ -9,6 +9,10 @@
 
   * <insert new release notes here>
 
+  * Add option on SkSurface::flush to pass in a GrBackendSurfaceMutableState which
+    we will set the gpu backend surface to be at the end of the flush.
+    https://review.skia.org/295567
+
   * Add GrContext function to set mutable state on a backend surface. Currently this
     is only used for setting vulkan VkImage layout and queue family.
     https://review.skia.org/293844