Callout, Drawer: minor optimization for detecting if content is an IMeasureObject

Author: joshtynjala

src/feathers/controls/Callout.hx

@@ -917,10 +917,10 @@ class Callout extends FeathersControl {
 		}
 
 		var measureContent:IMeasureObject = null;
-		if ((this._content is IMeasureObject)) {
-			measureContent = cast this._content;
-		}
 		if (this._content != null) {
+			if ((this._content is IMeasureObject)) {
+				measureContent = cast this._content;
+			}
 			var oldIgnoreContentResize = this._ignoreContentResize;
 			this._ignoreContentResize = true;
 			MeasurementsUtil.resetFluidlyWithParentValues(this._contentMeasurements, this._content,

src/feathers/controls/Drawer.hx

@@ -547,10 +547,10 @@ class Drawer extends FeathersControl implements IOpenCloseToggle implements IFoc
 		}
 
 		var measureContent:IMeasureObject = null;
-		if ((this._content is IMeasureObject)) {
-			measureContent = cast this._content;
-		}
 		if (this._content != null) {
+			if ((this._content is IMeasureObject)) {
+				measureContent = cast this._content;
+			}
 			var oldIgnoreContentResize = this._ignoreContentResize;
 			this._ignoreContentResize = true;
 			MeasurementsUtil.resetFluidlyWithParentValues(this._contentMeasurements, this._content, this.explicitWidth, this.explicitHeight,