gpu: Expose GrContextPriv::abandoned in the public API.

TBR=bsalomon@google.com

Bug: 854416
Change-Id: Iab71ca6e4724a925b0b9791267aac5ddc34f5b15
Reviewed-on: https://skia-review.googlesource.com/137692
Reviewed-by: Khusal Sagar <khushalsagar@chromium.org>
Commit-Queue: Khusal Sagar <khushalsagar@chromium.org>
diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index ee0eff0..43c4cba 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -163,7 +163,7 @@
 }
 
 bool SkImage::isValid(GrContext* context) const {
-    if (context && context->contextPriv().abandoned()) {
+    if (context && context->abandoned()) {
         return false;
     }
     return as_IB(this)->onIsValid(context);