Watch out for SkFixed overflow in SkMipMap.cpp.

src/core/SkMipMap.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 "SkMipMap.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 210 matching lines @@
     SkASSERT(addr == baseAddr + size);
 
     return mipmap;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 //static int gCounter;
 
 static SkFixed compute_level(SkScalar scale) {
-    SkFixed s = SkAbs32(SkScalarToFixed(SkScalarInvert(scale)));
+    SkScalar inv = SkScalarAbs(SkScalarInvert(scale));
+    if (inv > 32767) {  // Watch out for SkFixed overflow.
+        inv = 32767;
+    }
+    SkFixed s = SkScalarToFixed(inv);
 
     if (s < SK_Fixed1) {
         return 0;
     }
     int clz = SkCLZ(s);
     SkASSERT(clz >= 1 && clz <= 15);
     return SkIntToFixed(15 - clz) + ((unsigned)(s << (clz + 1)) >> 16);
 }
 
 bool SkMipMap::extractLevel(SkScalar scale, Level* levelPtr) const {
@@ skipping 12 matching lines @@
     }
 
     if (level > fCount) {
         level = fCount;
     }
     if (levelPtr) {
         *levelPtr = fLevels[level - 1];
     }
     return true;
 }