[builtins] Provide Math.floor as TurboFan builtin.

src/js/math.js

Index: src/js/math.js
diff --git a/src/js/math.js b/src/js/math.js
index c17441db8064ec48c7f308a6e665060eb31acc90..99f5e009664e3da78884321de876ec2fea50bcc9 100644
--- a/src/js/math.js
+++ b/src/js/math.js
@@ -41,7 +41,7 @@ function MathAtan2JS(y, x) {
 
 // ECMA 262 - 15.8.2.6
 function MathCeil(x) {
-  return -%_MathFloor(-x);
+  return -%math_floor(-x);
 }
 
 // ECMA 262 - 15.8.2.8
@@ -49,11 +49,6 @@ function MathExp(x) {
   return %MathExpRT(TO_NUMBER(x));
 }
 
-// ECMA 262 - 15.8.2.9
-function MathFloorJS(x) {
-  return %_MathFloor(+x);
-}
-
 // ECMA 262 - 15.8.2.10
 function MathLog(x) {
   return %_MathLogRT(TO_NUMBER(x));
@@ -103,8 +98,8 @@ function MathSign(x) {
 // ES6 draft 09-27-13, section 20.2.2.34.
 function MathTrunc(x) {
   x = +x;
-  if (x > 0) return %_MathFloor(x);
-  if (x < 0) return -%_MathFloor(-x);
+  if (x > 0) return %math_floor(x);
+  if (x < 0) return -%math_floor(-x);
   // -0, 0 or NaN.
   return x;
 }
@@ -187,7 +182,7 @@ macro NEWTON_ITERATION_CBRT(x, approx)
 endmacro
 
 function CubeRoot(x) {
-  var approx_hi = MathFloorJS(%_DoubleHi(x) / 3) + 0x2A9F7893;
+  var approx_hi = %math_floor(%_DoubleHi(x) / 3) + 0x2A9F7893;
   var approx = %_ConstructDouble(approx_hi | 0, 0);
   approx = NEWTON_ITERATION_CBRT(x, approx);
   approx = NEWTON_ITERATION_CBRT(x, approx);
@@ -226,7 +221,6 @@ utils.InstallFunctions(GlobalMath, DONT_ENUM, [
   "abs", MathAbs,
   "ceil", MathCeil,
   "exp", MathExp,
-  "floor", MathFloorJS,
   "log", MathLog,
   "round", MathRound,
   "atan2", MathAtan2JS,
@@ -245,7 +239,6 @@ utils.InstallFunctions(GlobalMath, DONT_ENUM, [
 %SetForceInlineFlag(MathAtan2JS);
 %SetForceInlineFlag(MathCeil);
 %SetForceInlineFlag(MathClz32JS);
-%SetForceInlineFlag(MathFloorJS);
 %SetForceInlineFlag(MathRandom);
 %SetForceInlineFlag(MathSign);
 %SetForceInlineFlag(MathTrunc);
@@ -256,7 +249,6 @@ utils.InstallFunctions(GlobalMath, DONT_ENUM, [
 utils.Export(function(to) {
   to.MathAbs = MathAbs;
   to.MathExp = MathExp;
-  to.MathFloor = MathFloorJS;
   to.IntRandom = MathRandomRaw;
 });