Remove GrRenderTargetContextPriv and GrSurfaceContextPriv

I think this is vestigial from some time in the past where RTC was
public.

Also just expose the methods that add ops rather than have so many
friends + testingOnly versions.

Change-Id: I60d9fdff23b2d67039a7b37815da7ff9e73d8999
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/339158
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/GrSurfaceContext.cpp b/src/gpu/GrSurfaceContext.cpp
index c66b651..2a79b15 100644
--- a/src/gpu/GrSurfaceContext.cpp
+++ b/src/gpu/GrSurfaceContext.cpp
@@ -22,7 +22,6 @@
 #include "src/gpu/GrProxyProvider.h"
 #include "src/gpu/GrRecordingContextPriv.h"
 #include "src/gpu/GrRenderTargetContext.h"
-#include "src/gpu/GrSurfaceContextPriv.h"
 #include "src/gpu/SkGr.h"
 #include "src/gpu/effects/GrBicubicEffect.h"
 #include "src/gpu/effects/generated/GrColorMatrixFragmentProcessor.h"
@@ -127,9 +126,7 @@
 }
 
 #ifdef SK_DEBUG
-GrSingleOwner* GrSurfaceContext::singleOwner() {
-    return fContext->priv().singleOwner();
-}
+GrSingleOwner* GrSurfaceContext::singleOwner() const { return fContext->priv().singleOwner(); }
 #endif
 
 bool GrSurfaceContext::readPixels(GrDirectContext* dContext, const GrImageInfo& origDstInfo,