Drop FXSYS_ from math methods

This Cl drops the FXSYS_ from math methods which are the same on all
platforms.

Bug: pdfium:694
Change-Id: I85c9ff841fd9095b1434f67319847ba0cd9df7ac
Reviewed-on: https://pdfium-review.googlesource.com/3598
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
diff --git a/fpdfsdk/javascript/JS_Value.cpp b/fpdfsdk/javascript/JS_Value.cpp
index a0c286f..e9fa9a0 100644
--- a/fpdfsdk/javascript/JS_Value.cpp
+++ b/fpdfsdk/javascript/JS_Value.cpp
@@ -501,7 +501,7 @@
 }
 
 double _toInteger(double n) {
-  return (n >= 0) ? FXSYS_floor(n) : -FXSYS_floor(-n);
+  return (n >= 0) ? floor(n) : -floor(-n);
 }
 
 bool _isLeapYear(int year) {
@@ -509,9 +509,8 @@
 }
 
 int _DayFromYear(int y) {
-  return (int)(365 * (y - 1970.0) + FXSYS_floor((y - 1969.0) / 4) -
-               FXSYS_floor((y - 1901.0) / 100) +
-               FXSYS_floor((y - 1601.0) / 400));
+  return (int)(365 * (y - 1970.0) + floor((y - 1969.0) / 4) -
+               floor((y - 1901.0) / 100) + floor((y - 1601.0) / 400));
 }
 
 double _TimeFromYear(int y) {
@@ -529,7 +528,7 @@
 }
 
 int _Day(double t) {
-  return (int)FXSYS_floor(t / 86400000);
+  return (int)floor(t / 86400000);
 }
 
 int _YearFromTime(double t) {
@@ -699,7 +698,7 @@
   double y = _toInteger(nYear);
   double m = _toInteger(nMonth);
   double dt = _toInteger(nDate);
-  double ym = y + FXSYS_floor((double)m / 12);
+  double ym = y + floor((double)m / 12);
   double mn = _Mod(m, 12);
 
   double t = _TimeFromYearMonth((int)ym, (int)mn);