Add GrContextOptions flag to disable distance field path renderer.

src/gpu/GrPathRendererChain.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrPathRendererChain_DEFINED
 #define GrPathRendererChain_DEFINED
 
 #include "GrPathRenderer.h"
 
 #include "SkTypes.h"
 #include "SkTArray.h"
 
 class GrContext;
 
 /**
  * Keeps track of an ordered list of path renderers. When a path needs to be
  * drawn this list is scanned to find the most preferred renderer. To add your
  * path renderer to the list implement the GrPathRenderer::AddPathRenderers
  * function.
  */
 class GrPathRendererChain : public SkNoncopyable {
 public:
-    GrPathRendererChain(GrContext* context);
+    struct Options {
+        bool fDisableDistanceFieldRenderer = false;
+    };
+    GrPathRendererChain(GrContext* context, const Options&);
 
     ~GrPathRendererChain();
 
     /** Documents how the caller plans to use a GrPathRenderer to draw a path. It affects the PR
         returned by getPathRenderer */
     enum DrawType {
         kColor_DrawType,                    // draw to the color buffer, no AA
         kColorAntiAlias_DrawType,           // draw to color buffer, with partial coverage AA
         kStencilOnly_DrawType,              // draw just to the stencil buffer
         kStencilAndColor_DrawType,          // draw the stencil and color buffer, no AA
@@ skipping 13 matching lines @@
     // takes a ref and unrefs in destructor
     GrPathRenderer* addPathRenderer(GrPathRenderer* pr);
 
     enum {
         kPreAllocCount = 8,
     };
     SkSTArray<kPreAllocCount, GrPathRenderer*, true>    fChain;
 };
 
 #endif