emscripten: drop CanvasPixelArray support from cursor

src/video/emscripten/SDL_emscriptenmouse.c

@@ -92,28 +92,9 @@ Emscripten_CreateCursor(SDL_Surface* surface, int hot_x, int hot_y)
         var image = ctx.createImageData(w, h);
         var data = image.data;
         var src = pixels >> 2;
-        var dst = 0;
-        var num;
-        if (typeof CanvasPixelArray !== 'undefined' && data instanceof CanvasPixelArray) {
-            // IE10/IE11: ImageData objects are backed by the deprecated CanvasPixelArray,
-            // not UInt8ClampedArray. These don't have buffers, so we need to revert
-            // to copying a byte at a time. We do the undefined check because modern
-            // browsers do not define CanvasPixelArray anymore.
-            num = data.length;
-            while (dst < num) {
-                var val = HEAP32[src]; // This is optimized. Instead, we could do {{{ makeGetValue('buffer', 'dst', 'i32') }}};
-                data[dst  ] = val & 0xff;
-                data[dst+1] = (val >> 8) & 0xff;
-                data[dst+2] = (val >> 16) & 0xff;
-                data[dst+3] = (val >> 24) & 0xff;
-                src++;
-                dst += 4;
-            }
-        } else {
-            var data32 = new Int32Array(data.buffer);
-            num = data32.length;
-            data32.set(HEAP32.subarray(src, src + num));
-        }
+
+        var data32 = new Int32Array(data.buffer);
+        data32.set(HEAP32.subarray(src, src + data32.length));
 
         ctx.putImageData(image, 0, 0);
         var url = hot_x === 0 && hot_y === 0