Remove SkImage::MakeFromYUVATexturesCopyToExternal

It's no longer used by Chrome.

Inline helper that draws yuva->rgba into the now single use case.

Move yuva proxy making helper from SkImage_GpuBase to SkImage_GpuYUVA
since it is only used there now.

Remove gm that tested the API and associated helper code in YUVUtils.

Bug: skia:10632
Change-Id: If6bd49befa1d1098bb6a268b9d856794f7eb80c3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/342077
Reviewed-by: Adlai Holler <adlai@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/RELEASE_NOTES.txt b/RELEASE_NOTES.txt
index 7323013..553dff2 100644
--- a/RELEASE_NOTES.txt
+++ b/RELEASE_NOTES.txt
@@ -7,6 +7,9 @@
 Milestone 89
 ------------
 
+  * Removed previously deprecated SkImage::MakeFromYUVATexturesCopyToExternal.
+    https://review.skia.org/342077
+
   * Add versions of GrDirectContext::createBackendTexture and updateBackendTexture
     that take a GrSurfaceOrigin. The previous versions are deprecated.
     https://review.skia.org/341005