[Plot] Organize plot elements

Place elements of the PlotController into a separate
directory inside of the source folder for the plot
plug-in, in preparation for review and integration.
Part of ongoing plot transition to Angular, WTD-533.

platform/features/plot/src/elements/PlotPosition.js

@@ -0,0 +1,38 @@
+/*global define*/
+
+define(
+    [],
+    function () {
+        "use strict";
+
+        function PlotPosition(x, y, width, height, panZoomStack) {
+            var panZoom = panZoomStack.getPanZoom(),
+                origin = panZoom.origin,
+                dimensions = panZoom.dimensions,
+                position;
+
+            if (!dimensions || !origin) {
+                position = [];
+            } else {
+                position = [ x / width, (height - y) / height ].map(function (v, i) {
+                    return v * dimensions[i] + origin[i];
+                });
+            }
+
+            return {
+                getDomain: function () {
+                    return position[0];
+                },
+                getRange: function () {
+                    return position[1];
+                },
+                getPosition: function () {
+                    return position;
+                }
+            };
+
+        }
+
+        return PlotPosition;
+    }
+);