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

src/gpu/GrOvalRenderer.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrOvalRenderer.h"
 
 #include "GrBatchFlushState.h"
@@ skipping 1881 matching lines @@
 
 ///////////////////////////////////////////////////////////////////////////////
 
 GrDrawBatch* GrOvalRenderer::CreateArcBatch(GrColor color,
                                             const SkMatrix& viewMatrix,
                                             const SkRect& oval,
                                             SkScalar startAngle, SkScalar sweepAngle,
                                             bool useCenter,
                                             const GrStyle& style,
                                             const GrShaderCaps* shaderCaps) {
+    SkASSERT(!oval.isEmpty());
+    SkASSERT(sweepAngle);
     SkScalar width = oval.width();
+    if (SkScalarAbs(sweepAngle) >= 360.f) {
+        return nullptr;
+    }
     if (!SkScalarNearlyEqual(width, oval.height()) || !circle_stays_circle(viewMatrix)) {
         return nullptr;
     }
     SkPoint center = {oval.centerX(), oval.centerY()};
     CircleBatch::ArcParams arcParams = {
         SkDegreesToRadians(startAngle),
         SkDegreesToRadians(sweepAngle),
         useCenter
     };
     return CircleBatch::Create(color, viewMatrix, center, width/2.f, style, &arcParams);
@@ skipping 49 matching lines @@
 }
 
 DRAW_BATCH_TEST_DEFINE(RRectBatch) {
     SkMatrix viewMatrix = GrTest::TestMatrixRectStaysRect(random);
     GrColor color = GrRandomColor(random);
     const SkRRect& rrect = GrTest::TestRRectSimple(random);
     return create_rrect_batch(color, viewMatrix, rrect, GrTest::TestStrokeRec(random));
 }
 
 #endif