[Plot] Throttle updates

Throttle plot updates to subplots; WTD-1202.

platform/features/plot/bundle.json

@@ -22,7 +22,7 @@
             {
                 "key": "PlotController",
                 "implementation": "PlotController.js",
-                "depends": [ "$scope", "telemetryFormatter", "telemetryHandler" ]
+                "depends": [ "$scope", "telemetryFormatter", "telemetryHandler", "throttle" ]
             }
         ]
     }

platform/features/plot/src/PlotController.js

@@ -51,13 +51,14 @@ define(
          *
          * @constructor
          */
-        function PlotController($scope, telemetryFormatter, telemetryHandler) {
+        function PlotController($scope, telemetryFormatter, telemetryHandler, throttle) {
             var subPlotFactory = new SubPlotFactory(telemetryFormatter),
                 modeOptions = new PlotModeOptions([], subPlotFactory),
                 subplots = [],
                 cachedObjects = [],
                 updater,
                 handle,
+                scheduleUpdate,
                 domainOffset;
 
             // Populate the scope with axis information (specifically, options
@@ -89,9 +90,7 @@ define(
 
             // Update all sub-plots
             function update() {
-                modeOptions.getModeHandler()
-                    .getSubPlots()
-                    .forEach(updateSubplot);
+                scheduleUpdate();
             }
 
             // Reinstantiate the plot updater (e.g. because we have a
@@ -162,6 +161,12 @@ define(
 
             // Unsubscribe when the plot is destroyed
             $scope.$on("$destroy", releaseSubscription);
+            
+            // Create a throttled update function
+            scheduleUpdate = throttle(function () {
+                modeOptions.getModeHandler().getSubPlots()
+                    .forEach(updateSubplot);
+            });
 
             return {
                 /**

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

@@ -62,8 +62,6 @@ define(
                         points: buf.getLength()
                     };
                 });
-
-                subplot.update();
             }
 
             return {

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

@@ -58,8 +58,6 @@ define(
                     color: PlotPalette.getFloatColor(0),
                     points: buffer.getLength()
                 }];
-
-                subplot.update();
             }
 
             function plotTelemetry(prepared) {