Prevent LayoutTest setting -1 page scale factor.

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

Index: third_party/WebKit/Source/core/frame/PageScaleConstraints.cpp
diff --git a/third_party/WebKit/Source/core/frame/PageScaleConstraints.cpp b/third_party/WebKit/Source/core/frame/PageScaleConstraints.cpp
index 563265425618c79fd7cd3fe92aaa2ac57e97bdb5..8494f7d9bfacc9e5f498e978f81ab598c0509c58 100644
--- a/third_party/WebKit/Source/core/frame/PageScaleConstraints.cpp
+++ b/third_party/WebKit/Source/core/frame/PageScaleConstraints.cpp
@@ -58,8 +58,6 @@ void PageScaleConstraints::overrideWith(const PageScaleConstraints& other)
 
 float PageScaleConstraints::clampToConstraints(float pageScaleFactor) const
 {
-    if (pageScaleFactor == -1)

[bokan, 2016/09/19 19:01:21]

I don't think this is the right way to fix this. -1 is used as an "unset" value
here. In the case of initial scale, we need to differentiate between a set and
unset initial scale.

The actual page scale factor should never be -1 so we shouldn't ever call into
this method with the real page scale factor at -1. The bug is somewhere higher
up in the call stack.

-        return pageScaleFactor;
     if (minimumScale != -1)
         pageScaleFactor = std::max(pageScaleFactor, minimumScale);
     if (maximumScale != -1)