Add outline of new GrContext hierarchy

This begins the process of splitting GrContext into:

GrContext_Base, GrImageContext, GrRecordingContext and GrDirectContext.

Change-Id: I3c43045f2a5549b049e95791d65f74d4e16de36f
Reviewed-on: https://skia-review.googlesource.com/c/186878
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/GrDirectContext.cpp b/src/gpu/GrDirectContext.cpp
index 9e6075c..688278d 100644
--- a/src/gpu/GrDirectContext.cpp
+++ b/src/gpu/GrDirectContext.cpp
@@ -64,7 +64,8 @@
         SkASSERT(!fFPFactoryCache);
         fFPFactoryCache.reset(new GrSkSLFPFactoryCache());
         fThreadSafeProxy.reset(new GrContextThreadSafeProxy(fCaps, this->uniqueID(),
-                                                            fBackend, options, fFPFactoryCache));
+                                                            this->backend(),
+                                                            options, fFPFactoryCache));
 
         if (!INHERITED::initCommon(options)) {
             return false;