Rewrite NaN checks in terms of SkScalarIsNaN()

include/core/SkRect.h

 /*
  * 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.
  */
 
 #ifndef SkRect_DEFINED
 #define SkRect_DEFINED
 
@@ skipping 437 matching lines @@
      *  returns false.
      */
     bool isFinite() const {
         float accum = 0;
         accum *= fLeft;
         accum *= fTop;
         accum *= fRight;
         accum *= fBottom;
 
         // accum is either NaN or it is finite (zero).
-        SkASSERT(0 == accum || !(accum == accum));
+        SkASSERT(0 == accum || SkScalarIsNaN(accum));
 
         // value==value will be true iff value is not NaN
         // TODO: is it faster to say !accum or accum==accum?
-        return accum == accum;
+        return !SkScalarIsNaN(accum);
     }
 
     SkScalar    x() const { return fLeft; }
     SkScalar    y() const { return fTop; }
     SkScalar    left() const { return fLeft; }
     SkScalar    top() const { return fTop; }
     SkScalar    right() const { return fRight; }
     SkScalar    bottom() const { return fBottom; }
     SkScalar    width() const { return fRight - fLeft; }
     SkScalar    height() const { return fBottom - fTop; }
@@ skipping 388 matching lines @@
      *  cast-safe way to treat the rect as an array of (4) SkScalars.
      */
     const SkScalar* asScalars() const { return &fLeft; }
 
     void dump(bool asHex) const;
     void dump() const { this->dump(false); }
     void dumpHex() const { this->dump(true); }
 };
 
 #endif