In GrShape detect that stroked axis-aligned lines are rrects.

src/gpu/GrStyle.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 GrStyle_DEFINED
 #define GrStyle_DEFINED
 
@@ skipping 33 matching lines @@
         kPathEffectOnly,
         kPathEffectAndStrokeRec
     };
 
     /**
      * Optional flags for computing keys that may remove unnecessary variation in the key due to
      * style settings that don't affect particular classes of geometry.
      */
     enum KeyFlags {
         // The shape being styled has no open contours.
-        kClosed_KeyFlag = 0x1
+        kClosed_KeyFlag = 0x1,
+        // The shape being styled doesn't have any joins and so isn't affected by join type.
+        kNoJoins_KeyFlag = 0x2
     };
 
     /**
      * Computes the key length for a GrStyle. The return will be negative if it cannot be turned
      * into a key. This occurs when there is a path effect that is not a dash. The key can
      * either reflect just the path effect (if one) or the path effect and the strokerec. Note
      * that a simple fill has a zero sized key.
      */
     static int KeySize(const GrStyle&, Apply, uint32_t flags = 0);
 
@@ skipping 137 matching lines @@
     };
 
     bool applyPathEffect(SkPath* dst, SkStrokeRec* strokeRec, const SkPath& src) const;
 
     SkStrokeRec         fStrokeRec;
     sk_sp<SkPathEffect> fPathEffect;
     DashInfo            fDashInfo;
 };
 
 #endif