Remove workaround for WebKit bug 44083.

This was fixed in 2010, so I think it’s safe to remove the workaround now.

d3.js

@@ -1091,27 +1091,12 @@
   d3.mouse = function(container) {
     return d3_mousePoint(container, d3_eventSource());
   };
-  var d3_mouse_bug44083 = /WebKit/.test(d3_window.navigator.userAgent) ? -1 : 0;
   function d3_mousePoint(container, e) {
     if (e.changedTouches) e = e.changedTouches[0];
     var svg = container.ownerSVGElement || container;
     if (svg.createSVGPoint) {
       var point = svg.createSVGPoint();
-      if (d3_mouse_bug44083 < 0 && (d3_window.scrollX || d3_window.scrollY)) {
-        svg = d3.select("body").append("svg").style({
-          position: "absolute",
-          top: 0,
-          left: 0,
-          margin: 0,
-          padding: 0,
-          border: "none"
-        }, "important");
-        var ctm = svg[0][0].getScreenCTM();
-        d3_mouse_bug44083 = !(ctm.f || ctm.e);
-        svg.remove();
-      }
-      if (d3_mouse_bug44083) point.x = e.pageX, point.y = e.pageY; else point.x = e.clientX, 
-      point.y = e.clientY;
+      point.x = e.clientX, point.y = e.clientY;
       point = point.matrixTransform(container.getScreenCTM().inverse());
       return [ point.x, point.y ];
     }

src/event/mouse.js

@@ -4,29 +4,12 @@ d3.mouse = function(container) {
   return d3_mousePoint(container, d3_eventSource());
 };
 
-// https://bugs.webkit.org/show_bug.cgi?id=44083
-var d3_mouse_bug44083 = /WebKit/.test(d3_window.navigator.userAgent) ? -1 : 0;
-
 function d3_mousePoint(container, e) {
   if (e.changedTouches) e = e.changedTouches[0];
   var svg = container.ownerSVGElement || container;
   if (svg.createSVGPoint) {
     var point = svg.createSVGPoint();
-    if (d3_mouse_bug44083 < 0 && (d3_window.scrollX || d3_window.scrollY)) {
-      svg = d3.select("body").append("svg").style({
-        position: "absolute",
-        top: 0,
-        left: 0,
-        margin: 0,
-        padding: 0,
-        border: "none"
-      }, "important");
-      var ctm = svg[0][0].getScreenCTM();
-      d3_mouse_bug44083 = !(ctm.f || ctm.e);
-      svg.remove();
-    }
-    if (d3_mouse_bug44083) point.x = e.pageX, point.y = e.pageY;
-    else point.x = e.clientX, point.y = e.clientY;
+    point.x = e.clientX, point.y = e.clientY;
     point = point.matrixTransform(container.getScreenCTM().inverse());
     return [point.x, point.y];
   }