Use an abstract base class instead of IVectorContext

By having the abstract methods in the base class, subclasses can simply
override the methods they actually provide.
Additionally, this change fixes a regression in webgl canvas immediate.

src/ol/render/vectorcontext.js

@@ -0,0 +1,116 @@
+goog.provide('ol.render.VectorContext');
+
+
+
+/**
+ * @constructor
+ * @struct
+ */
+ol.render.VectorContext = function() {
+};
+
+
+/**
+ * @param {number} zIndex Z index.
+ * @param {function(ol.render.VectorContext)} callback Callback.
+ */
+ol.render.VectorContext.prototype.drawAsync = goog.abstractMethod;
+
+
+/**
+ * @param {ol.geom.Circle} circleGeometry Circle geometry.
+ * @param {ol.Feature} feature Feature,
+ */
+ol.render.VectorContext.prototype.drawCircleGeometry = goog.abstractMethod;
+
+
+/**
+ * @param {ol.Feature} feature Feature.
+ * @param {ol.style.Style} style Style.
+ */
+ol.render.VectorContext.prototype.drawFeature = goog.abstractMethod;
+
+
+/**
+ * @param {ol.geom.GeometryCollection} geometryCollectionGeometry Geometry
+ *     collection.
+ * @param {ol.Feature} feature Feature.
+ */
+ol.render.VectorContext.prototype.drawGeometryCollectionGeometry =
+    goog.abstractMethod;
+
+
+/**
+ * @param {ol.geom.LineString} lineStringGeometry Line string geometry.
+ * @param {ol.Feature} feature Feature.
+ */
+ol.render.VectorContext.prototype.drawLineStringGeometry =
+    goog.abstractMethod;
+
+
+/**
+ * @param {ol.geom.MultiLineString} multiLineStringGeometry
+ *     MultiLineString geometry.
+ * @param {ol.Feature} feature Feature.
+ */
+ol.render.VectorContext.prototype.drawMultiLineStringGeometry =
+    goog.abstractMethod;
+
+
+/**
+ * @param {ol.geom.MultiPoint} multiPointGeometry MultiPoint geometry.
+ * @param {ol.Feature} feature Feature.
+ */
+ol.render.VectorContext.prototype.drawMultiPointGeometry = goog.abstractMethod;
+
+
+/**
+ * @param {ol.geom.MultiPolygon} multiPolygonGeometry MultiPolygon geometry.
+ * @param {ol.Feature} feature Feature.
+ */
+ol.render.VectorContext.prototype.drawMultiPolygonGeometry =
+    goog.abstractMethod;
+
+
+/**
+ * @param {ol.geom.Point} pointGeometry Point geometry.
+ * @param {ol.Feature} feature Feature.
+ */
+ol.render.VectorContext.prototype.drawPointGeometry = goog.abstractMethod;
+
+
+/**
+ * @param {ol.geom.Polygon} polygonGeometry Polygon geometry.
+ * @param {ol.Feature} feature Feature.
+ */
+ol.render.VectorContext.prototype.drawPolygonGeometry = goog.abstractMethod;
+
+
+/**
+ * @param {Array.<number>} flatCoordinates Flat coordinates.
+ * @param {number} offset Offset.
+ * @param {number} end End.
+ * @param {number} stride Stride.
+ * @param {ol.geom.Geometry} geometry Geometry.
+ * @param {ol.Feature} feature Feature.
+ */
+ol.render.VectorContext.prototype.drawText = goog.abstractMethod;
+
+
+/**
+ * @param {ol.style.Fill} fillStyle Fill style.
+ * @param {ol.style.Stroke} strokeStyle Stroke style.
+ */
+ol.render.VectorContext.prototype.setFillStrokeStyle = goog.abstractMethod;
+
+
+/**
+ * @param {ol.style.Image} imageStyle Image style.
+ */
+ol.render.VectorContext.prototype.setImageStyle = goog.abstractMethod;
+
+
+/**
+ * @param {ol.style.Text} textStyle Text style.
+ */
+ol.render.VectorContext.prototype.setTextStyle = goog.abstractMethod;