GUACAMOLE-884: Leverage createImageBitmap() for reading image data where supported.

Some browsers suffer from a memory leak when reading image data
repeatedly using the Image object. Reading from Blobs does not exhibit
the same behavior. While reading from Blobs has previously been seen to
perform poorly compared to data URIs, this was observed when reading
using createObjectURL(). The createImageBitmap() function appears to
perform identically to reading data URIs using Image.

guacamole-common-js/src/main/webapp/modules/Client.js

@@ -1190,13 +1190,10 @@ Guacamole.Client = function(tunnel) {
 
             // Create stream
             var stream = streams[stream_index] = new Guacamole.InputStream(guac_client, stream_index);
-            var reader = new Guacamole.DataURIReader(stream, mimetype);
 
-            // Draw image when stream is complete
-            reader.onend = function drawImageBlob() {
-                display.setChannelMask(layer, channelMask);
-                display.draw(layer, x, y, reader.getURI());
-            };
+            // Draw received contents once decoded
+            display.setChannelMask(layer, channelMask);
+            display.drawStream(layer, x, y, stream, mimetype);
 
         },