Prevent LayoutTest setting -1 page scale factor.

third_party/WebKit/Source/core/frame/PageScaleConstraints.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 40 matching lines @@
         minimumScale = other.minimumScale;
     if (other.maximumScale != -1)
         maximumScale = other.maximumScale;
     if (!other.layoutSize.isZero())
         layoutSize = other.layoutSize;
     clampAll();
 }
 
 float PageScaleConstraints::clampToConstraints(float pageScaleFactor) const
 {
-    if (pageScaleFactor == -1)
-        return pageScaleFactor;
     if (minimumScale != -1)
         pageScaleFactor = std::max(pageScaleFactor, minimumScale);
     if (maximumScale != -1)
         pageScaleFactor = std::min(pageScaleFactor, maximumScale);
     return pageScaleFactor;
 }
 
 void PageScaleConstraints::clampAll()
 {
     if (minimumScale != -1 && maximumScale != -1)
@@ skipping 25 matching lines @@
 
 bool PageScaleConstraints::operator==(const PageScaleConstraints& other) const
 {
     return layoutSize == other.layoutSize
         && initialScale == other.initialScale
         && minimumScale == other.minimumScale
         && maximumScale == other.maximumScale;
 }
 
 } // namespace blink