Add mode validation to PtProcRec::init.

src/core/SkDraw.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #define __STDC_LIMIT_MACROS
 
 #include "SkDraw.h"
 #include "SkBlitter.h"
@@ skipping 425 matching lines @@
         r.fRight = x + radius;
         r.fBottom = y + radius;
 
         SkScan::AntiFillXRect(r, *rec.fRC, blitter);
     }
 }
 
 // If this guy returns true, then chooseProc() must return a valid proc
 bool PtProcRec::init(SkCanvas::PointMode mode, const SkPaint& paint,
                      const SkMatrix* matrix, const SkRasterClip* rc) {
+    if ((unsigned)mode > (unsigned)SkCanvas::kPolygon_PointMode) {
+        return false;
+    }
+
     if (paint.getPathEffect()) {
         return false;
     }
     SkScalar width = paint.getStrokeWidth();
     if (0 == width) {
         fMode = mode;
         fPaint = &paint;
         fClip = NULL;
         fRC = rc;
         fRadius = SK_FixedHalf;
@@ skipping 1807 matching lines @@
         mask->fImage = SkMask::AllocImage(size);
         memset(mask->fImage, 0, mask->computeImageSize());
     }
 
     if (SkMask::kJustComputeBounds_CreateMode != mode) {
         draw_into_mask(*mask, devPath, style);
     }
 
     return true;
 }