Accept custom isLoaded method in findLoadedTiles method

src/ol/renderer/canvas/canvastilelayerrenderer.js

@@ -129,8 +129,11 @@ ol.renderer.canvas.TileLayer.prototype.renderFrame =
   var tilesToDrawByZ = {};
   tilesToDrawByZ[z] = {};
 
+  function isLoaded(tile) {
+    return !goog.isNull(tile) && tile.getState() == ol.TileState.LOADED;
+  }
   var findLoadedTiles = goog.bind(tileSource.findLoadedTiles, tileSource,
-      tilesToDrawByZ);
+      tilesToDrawByZ, isLoaded);
 
   var allTilesLoaded = true;
   var tile, tileCenter, tileCoord, tileState, x, y;

src/ol/renderer/dom/domtilelayerrenderer.js

@@ -93,8 +93,11 @@ ol.renderer.dom.TileLayer.prototype.renderFrame =
   var tilesToDrawByZ = {};
   tilesToDrawByZ[z] = {};
 
+  function isLoaded(tile) {
+    return !goog.isNull(tile) && tile.getState() == ol.TileState.LOADED;
+  }
   var findLoadedTiles = goog.bind(tileSource.findLoadedTiles, tileSource,
-      tilesToDrawByZ);
+      tilesToDrawByZ, isLoaded);
 
   var allTilesLoaded = true;
   var tile, tileCenter, tileCoord, tileState, x, y;

src/ol/renderer/webgl/webgltilelayerrenderer.js

@@ -365,8 +365,12 @@ ol.renderer.webgl.TileLayer.prototype.renderFrame =
     var tilesToDrawByZ = {};
     tilesToDrawByZ[z] = {};
 
+    function isLoaded(tile) {
+      return !goog.isNull(tile) && tile.getState() == ol.TileState.LOADED &&
+          mapRenderer.isTileTextureLoaded(tile);
+    }
     var findLoadedTiles = goog.bind(tileSource.findLoadedTiles, tileSource,
-        tilesToDrawByZ);
+        tilesToDrawByZ, isLoaded);
 
     var tilesToLoad = new goog.structs.PriorityQueue();