add callbacks to Images that wrap client-provided content

BUG=skia:

Review URL: https://codereview.chromium.org/1169553003
diff --git a/src/gpu/GrSurface.cpp b/src/gpu/GrSurface.cpp
index 678755a..c052a23 100644
--- a/src/gpu/GrSurface.cpp
+++ b/src/gpu/GrSurface.cpp
@@ -125,3 +125,13 @@
     }
     return false;
 }
+
+void GrSurface::onRelease() {
+    this->invokeReleaseProc();
+    this->INHERITED::onRelease();
+}
+
+void GrSurface::onAbandon() {
+    this->invokeReleaseProc();
+    this->INHERITED::onAbandon();
+}