Rename GrDrawContext to GrRenderTargetContext

This is in preparation for GrTextureContext and GrSurfaceContext

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4030

Change-Id: Ie58c93052e68f3f1f5fe8d15d63760de274a6fbd
Reviewed-on: https://skia-review.googlesource.com/4030
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/gm/convexpolyeffect.cpp b/gm/convexpolyeffect.cpp
index 44471e5..e06fa97 100644
--- a/gm/convexpolyeffect.cpp
+++ b/gm/convexpolyeffect.cpp
@@ -13,7 +13,7 @@
 
 #include "GrContext.h"
 #include "GrDefaultGeoProcFactory.h"
-#include "GrDrawContextPriv.h"
+#include "GrRenderTargetContextPriv.h"
 #include "GrPathUtils.h"
 #include "GrTest.h"
 #include "SkColorPriv.h"
@@ -153,8 +153,9 @@
     }
 
     void onDraw(SkCanvas* canvas) override {
-        GrDrawContext* drawContext = canvas->internal_private_accessTopLayerDrawContext();
-        if (!drawContext) {
+        GrRenderTargetContext* renderTargetContext =
+            canvas->internal_private_accessTopLayerRenderTargetContext();
+        if (!renderTargetContext) {
             skiagm::GM::DrawGpuOnlyMessage(canvas);
             return;
         }
@@ -184,7 +185,8 @@
 
                 SkAutoTUnref<GrDrawBatch> batch(new PolyBoundsBatch(p.getBounds(), 0xff000000));
 
-                drawContext->drawContextPriv().testingOnly_drawBatch(grPaint, batch);
+                renderTargetContext->renderTargetContextPriv().testingOnly_drawBatch(grPaint,
+                                                                                     batch);
 
                 x += SkScalarCeilToScalar(path->getBounds().width() + kDX);
             }
@@ -223,7 +225,8 @@
 
                 SkAutoTUnref<GrDrawBatch> batch(new PolyBoundsBatch(rect, 0xff000000));
 
-                drawContext->drawContextPriv().testingOnly_drawBatch(grPaint, batch);
+                renderTargetContext->renderTargetContextPriv().testingOnly_drawBatch(grPaint,
+                                                                                     batch);
 
                 x += SkScalarCeilToScalar(rect.width() + kDX);
             }