Layer: refactor openPopup/openTooltip: use common function DivOverlay…

…._open

more solid devision between functions (_prepareOpen was less clear)

src/layer/DivOverlay.js

@@ -160,7 +160,9 @@ export var DivOverlay = Layer.extend({
 		return this;
 	},
 
-	_prepareOpen: function (parent, layer, latlng) {
+	_open: function (parent, layer, latlng) {
+		if (!parent._map) { return; }
+
 		if (!(layer instanceof Layer)) {
 			latlng = layer;
 			layer = parent;
@@ -191,7 +193,8 @@ export var DivOverlay = Layer.extend({
 		// update the overlay (content, layout, ect...)
 		this.update();
 
-		return latlng;
+		// open the overlay on the map
+		parent._map._openOverlay(this.constructor, this, latlng);
 	},
 
 	_updateContent: function () {

src/layer/Popup.js

@@ -408,11 +408,8 @@ Layer.include({
 	// @method openPopup(latlng?: LatLng): this
 	// Opens the bound popup at the specified `latlng` or at the default popup anchor if no `latlng` is passed.
 	openPopup: function (layer, latlng) {
-		if (this._popup && this._map) {
-			latlng = this._popup._prepareOpen(this, layer, latlng);
-
-			// open the popup on the map
-			this._map.openPopup(this._popup, latlng);
+		if (this._popup) {
+			this._popup._open(this, layer, latlng);
 		}
 
 		return this;

src/layer/Tooltip.js

@@ -313,11 +313,7 @@ Layer.include({
 	// @method openTooltip(latlng?: LatLng): this
 	// Opens the bound tooltip at the specified `latlng` or at the default tooltip anchor if no `latlng` is passed.
 	openTooltip: function (layer, latlng) {
-		if (this._tooltip && this._map) {
-			latlng = this._tooltip._prepareOpen(this, layer, latlng);
-
-			// open the tooltip on the map
-			this._map.openTooltip(this._tooltip, latlng);
+		if (this._tooltip && this._tooltip._open(this, layer, latlng)) {
 
 			// Tooltip container may not be defined if not permanent and never
 			// opened.