Move internal calls from GrContext to GrContextPriv

A mechanical bulk move just to get these out of the public API.

TBR=bsalomon@google.com
Change-Id: I813efbd54a09dd448275697c0e50947753a5cfd3
Reviewed-on: https://skia-review.googlesource.com/112262
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
diff --git a/tests/RectangleTextureTest.cpp b/tests/RectangleTextureTest.cpp
index 8994f56..08cedd0 100644
--- a/tests/RectangleTextureTest.cpp
+++ b/tests/RectangleTextureTest.cpp
@@ -22,8 +22,8 @@
 // skbug.com/5932
 static void test_basic_draw_as_src(skiatest::Reporter* reporter, GrContext* context,
                                    sk_sp<GrTextureProxy> rectProxy, uint32_t expectedPixelValues[]) {
-    sk_sp<GrRenderTargetContext> rtContext(
-            context->makeDeferredRenderTargetContext(SkBackingFit::kExact, rectProxy->width(),
+    sk_sp<GrRenderTargetContext> rtContext(context->contextPriv().makeDeferredRenderTargetContext(
+                                                     SkBackingFit::kExact, rectProxy->width(),
                                                      rectProxy->height(), rectProxy->config(),
                                                      nullptr));
     for (auto filter : {GrSamplerState::Filter::kNearest,