Respecify SkCanvas::drawArc, consolidate conversion to SkPath, add GM for oddball drawArcs

src/core/SkPathPriv.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkPathPriv_DEFINED
 #define SkPathPriv_DEFINED
 
@@ skipping 73 matching lines @@
         path.fPathRef->addGenIDChangeListener(listener);
     }
 
     /**
      * This returns true for a rect that begins and ends at the same corner and has either a move
      * followed by four lines or a move followed by 3 lines and a close. None of the parameters are
      * optional. This does not permit degenerate line or point rectangles.
      */
     static bool IsSimpleClosedRect(const SkPath& path, SkRect* rect, SkPath::Direction* direction,
                                    unsigned* start);
+
+    /**
+     * Creates a path from arc params using the semantics of SkCanvas::drawArc. This function
+     * assumes empty ovals and zero sweeps have already been filtered out.
+     */
+    static void CreateDrawArcPath(SkPath* path, const SkRect& oval, SkScalar startAngle,
+                                  SkScalar sweepAngle, bool useCenter, bool isFillNoPathEffect);
 };
 
 #endif