Make GrShape compute keys for short paths from path data instead of using the gen id.

src/gpu/GrShape.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrShape_DEFINED
 #define GrShape_DEFINED
 
@@ skipping 16 matching lines @@
  * to geometric information and is included in the new shape's key. When the same style is applied
  * to two shapes that reflect the same underlying geometry the computed keys of the stylized shapes
  * will be the same.
  *
  * Currently this can only be constructed from a path, rect, or rrect though it can become a path
  * applying style to the geometry. The idea is to expand this to cover most or all of the geometries
  * that have SkCanvas::draw APIs.
  */
 class GrShape {
 public:
+    // Keys for paths may be extracted from the path data for small paths. Clients aren't supposed
+    // to have to worry about this. This value is exposed for unit tests.
+    static constexpr int kMaxKeyFromDataVerbCnt = 10;
+
     GrShape() { this->initType(Type::kEmpty); }
 
     explicit GrShape(const SkPath& path) : GrShape(path, GrStyle::SimpleFill()) {}
 
     explicit GrShape(const SkRRect& rrect) : GrShape(rrect, GrStyle::SimpleFill()) {}
 
     explicit GrShape(const SkRect& rect) : GrShape(rect, GrStyle::SimpleFill()) {}
 
     GrShape(const SkPath& path, const GrStyle& style) : fStyle(style) {
         this->initType(Type::kPath, &path);
@@ skipping 403 matching lines @@
         } fPathData;
         struct {
             SkPoint                     fPts[2];
             bool                        fInverted;
         } fLineData;
     };
     GrStyle                     fStyle;
     SkAutoSTArray<8, uint32_t>  fInheritedKey;
 };
 #endif