[CSS Exclusions] Programmatic layout tests fail when subpixel layout is disabled

LayoutTests/fast/exclusions/resources/rounded-rectangle.js

 if (window.internals)
     window.internals.settings.setCSSExclusionsEnabled(true);
 
 function defined(value) { return typeof value !== "undefined"; }
 
 function convertToRoundedRect(dimensions) {
     if (defined(dimensions.shapeCenterX) && defined(dimensions.shapeCenterY)) {
         if (defined(dimensions.shapeRadius)) {
             // Convert a circle.
             dimensions.shapeX = dimensions.shapeCenterX - dimensions.shapeRadius;
@@ skipping 77 matching lines @@
         paddingTop.style.width = dimensions.width + "px";
         paddingTop.style.height = dimensions.shapeY + "px";
         element.appendChild(paddingTop);
     }
 
     for (var y = 0; y < dimensions.shapeHeight; y+= floatHeight) {
         var inset = simpleRectangle ? 0 : xInset(dimensions, y, y + lineHeight);
 
         var paddingLeft = document.createElement("div");
         paddingLeft.setAttribute("class", "float left");
-        paddingLeft.style.width = SubPixelLayout.roundLineLeft(dimensions.shapeX + inset) + "px";
+        paddingLeft.style.width = SubPixelLayout.snapToLayoutUnit(dimensions.shapeX + inset) + "px";
         element.appendChild(paddingLeft);
 
         var paddingRight = document.createElement("div");
         paddingRight.setAttribute("class", "float right");
-        paddingRight.style.width = SubPixelLayout.roundLineRight((dimensions.width - dimensions.shapeWidth - dimensions.shapeX) + inset) + "px";
+        paddingRight.style.width = SubPixelLayout.snapToLayoutUnit((dimensions.width - dimensions.shapeWidth - dimensions.shapeX) + inset) + "px";
         element.appendChild(paddingRight);
     }
 }
 
 function simulateShapeOutline(elementId, stylesheet, dimensions) {
     stylesheet.insertRule("#" + elementId + "{ position: relative; }");
     stylesheet.insertRule("#" + elementId + "::before { "
                             + "content: ' '; "
                             + "display: block; "
                             + "position: absolute; "
@@ skipping 101 matching lines @@
     // For simulating, we ignore the x and y values, since we're not attempting
     // to draw the float's content in the right place, we just want to simulate
     // the shape's effect.
     if (floatValue == "right")
         dimensions.shapeX = -dimensions.shapeWidth;
     else 
         dimensions.shapeX = 0;
     dimensions.shapeY = 0;
     simulateShapeOutline(elementId, stylesheet, dimensions);
 }