Fix issue where GrStyle::applyToPath exited before applying stroke

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 117 matching lines @@
 
     const SkStrokeRec& strokeRec() const { return fStrokeRec; }
 
     /** Hairline or fill styles without path effects make no alterations to a geometry. */
     bool applies() const {
         return this->pathEffect() || (!fStrokeRec.isFillStyle() && !fStrokeRec.isHairlineStyle());
     }
 
     /**
      * Applies just the path effect and returns remaining stroke information. This will fail if
-     * there is no path effect.
+     * there is no path effect. dst may or may not have been overwritten on failure.
      */
-    bool applyPathEffectToPath(SkPath* dst, SkStrokeRec* remainingStoke, const SkPath& src) const;
+    bool SK_WARN_UNUSED_RESULT applyPathEffectToPath(SkPath* dst, SkStrokeRec* remainingStoke,
+                                                     const SkPath& src) const;
 
     /** If this succeeds then the result path should be filled or hairlined as indicated by the
         returned SkStrokeRec::InitStyle value. Will fail if there is no path effect and the
-        strokerec doesn't change the geometry. */
-    bool applyToPath(SkPath* dst, SkStrokeRec::InitStyle* fillOrHairline, const SkPath& src) const;
+        strokerec doesn't change the geometry. When this fails the outputs may or may not have
+        been overwritten.
+      */
+    bool SK_WARN_UNUSED_RESULT applyToPath(SkPath* dst, SkStrokeRec::InitStyle* fillOrHairline,
+                                           const SkPath& src) const;
 
     /** Given bounds of a path compute the bounds of path with the style applied. */
     void adjustBounds(SkRect* dst, const SkRect& src) const {
         if (this->pathEffect()) {
             this->pathEffect()->computeFastBounds(dst, src);
         } else {
             SkScalar radius = fStrokeRec.getInflationRadius();
             *dst = src.makeOutset(radius, radius);
         }
     }
@@ skipping 19 matching lines @@
         SkScalar                    fPhase;
         SkAutoSTArray<4, SkScalar>  fIntervals;
     };
 
     SkStrokeRec         fStrokeRec;
     sk_sp<SkPathEffect> fPathEffect;
     DashInfo            fDashInfo;
 };
 
 #endif