[Browse] Add JSDoc

Add in-line documentation to controller which supports the
moveable splitter in Browse mode, WTD-747.

platform/commonUI/general/src/controllers/SplitPaneController.js

@@ -5,35 +5,46 @@ define(
     function () {
         "use strict";
 
+        /**
+         * Controller for the splitter in Browse mode. Current implementation
+         * uses many hard-coded constants; this could be generalized.
+         * @constructor
+         */
         function SplitPaneController() {
             var minimum = 120,
                 maximum = 600,
                 current = 200,
-                start = 200,
+                start = 200;
-                style;
-
-            function updateStyle() {
-                style = { left: current + 'px' };
-            }
-
-            updateStyle();
 
             return {
-                style: function () {
+                /**
-                    return style;
+                 * Get the current position of the splitter, in pixels
-                },
+                 * from the left edge.
+                 * @returns {number} position of the splitter, in pixels
+                 */
                 state: function () {
                     return current;
                 },
+                /**
+                 * Begin moving the splitter; this will note the splitter's
+                 * current position, which is necessary for correct
+                 * interpretation of deltas provided by mct-drag.
+                 */
                 startMove: function () {
                     start = current;
                 },
+                /**
+                 * Move the splitter a number of pixels to the right
+                 * (negative numbers move the splitter to the left.)
+                 * This movement is relative to the position of the
+                 * splitter when startMove was last invoked.
+                 * @param {number} delta number of pixels to move
+                 */
                 move: function (delta) {
                     current = Math.min(
                         maximum,
                         Math.max(minimum, start + delta)
                     );
-                    updateStyle();
                 }
             };
         }