fix typo: add missing const

include/core/SkCanvas.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkCanvas_DEFINED
 #define SkCanvas_DEFINED
 
@@ skipping 1037 matching lines @@
         @param indexCount number of entries in the indices array (if not null)
         @param paint Specifies the shader/texture if present.
     */
     void drawVertices(VertexMode vmode, int vertexCount,
                       const SkPoint vertices[], const SkPoint texs[],
                       const SkColor colors[], SkXfermode* xmode,
                       const uint16_t indices[], int indexCount,
                       const SkPaint& paint);
     void drawVertices(VertexMode vmode, int vertexCount,
                       const SkPoint vertices[], const SkPoint texs[],
-                      const SkColor colors[], sk_sp<SkXfermode>& xmode,
+                      const SkColor colors[], const sk_sp<SkXfermode>& xmode,
                       const uint16_t indices[], int indexCount,
                       const SkPaint& paint) {
         this->drawVertices(vmode, vertexCount, vertices, texs, colors, xmode.get(),
                            indices, indexCount, paint);
     }
 
     /**
      Draw a cubic coons patch
 
      @param cubic specifies the 4 bounding cubic bezier curves of a patch with clockwise order
@@ skipping 497 matching lines @@
 
 class SkCanvasClipVisitor {
 public:
     virtual ~SkCanvasClipVisitor();
     virtual void clipRect(const SkRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipRRect(const SkRRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipPath(const SkPath&, SkRegion::Op, bool antialias) = 0;
 };
 
 #endif