[Plot] Add initial stack-plot implementation

Add initial implementation of stacked mode for
Plot view. Note that this will not stack correctly
due to markup/style issues. WTD-625.

platform/features/plot/src/modes/PlotModeOptions.js

@@ -1,15 +1,15 @@
 /*global define*/
 
 define(
-    ["./PlotOverlayMode"],
+    ["./PlotOverlayMode", "./PlotStackMode"],
-    function (PlotOverlayMode, PlotStackedMode) {
+    function (PlotOverlayMode, PlotStackMode) {
         "use strict";
 
         var STACKED = {
                 key: "stacked",
                 name: "Stacked",
                 glyph: "8",
-                factory: PlotOverlayMode
+                factory: PlotStackMode
             },
             OVERLAID = {
                 key: "overlaid",

platform/features/plot/src/modes/PlotStackMode.js

@@ -0,0 +1,71 @@
+/*global define*/
+
+define(
+    ["../SubPlot", "../elements/PlotPalette", "../elements/PlotPanZoomStack"],
+    function (SubPlot, PlotPalette, PlotPanZoomStack) {
+        "use strict";
+
+        function PlotStackMode(telemetryObjects) {
+            var domainOffset,
+                panZoomStack = new PlotPanZoomStack([], []),
+                subplots = telemetryObjects.map(function (telemetryObject) {
+                    return new SubPlot([telemetryObject], panZoomStack);
+                });
+
+            function plotTelemetryTo(subplot, prepared, index) {
+                var buffer = prepared.getBuffers()[index];
+
+                // Track the domain offset, used to bias domain values
+                // to minimize loss of precision when converted to 32-bit
+                // floating point values for display.
+                subplot.setDomainOffset(prepared.getDomainOffset());
+
+                // Draw the buffers. Always use the 0th color
+                subplot.getDrawingObject().lines = [{
+                    buffer: buffer,
+                    color: PlotPalette.getFloatColor(0),
+                    points: buffer.length / 2
+                }];
+
+                subplot.update();
+            }
+
+            function plotTelemetry(prepared) {
+                 // Fit to the boundaries of the data, but don't
+                // override any user-initiated pan-zoom changes.
+                panZoomStack.setBasePanZoom(
+                    prepared.getOrigin(),
+                    prepared.getDimensions()
+                );
+
+                subplots.forEach(function (subplot, index) {
+                    plotTelemetryTo(subplot, prepared, index);
+                });
+            }
+
+            return {
+                plotTelemetry: plotTelemetry,
+                getSubPlots: function () {
+                    return subplots;
+                },
+                isZoomed: function () {
+                    return panZoomStack.getDepth() > 1;
+                },
+                stepBackPanZoom: function () {
+                    panZoomStack.pop();
+                    subplots.forEach(function (subplot) {
+                        subplot.update();
+                    });
+                },
+                unzoom: function () {
+                    panZoomStack.clearPanZoom();
+                    subplots.forEach(function (subplot) {
+                        subplot.update();
+                    });
+                }
+            };
+        }
+
+        return PlotStackMode;
+    }
+);