Center the desktop if it's smaller than the frame.

remoting/webapp/me2mom/client_session.js

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview
  * Session class that handles creation and teardown of a remoting session.
  *
  * This abstracts a <embed> element and controls the plugin which does the
  * actual remoting work.  There should be no UI code inside this class.  It
@@ skipping 334 matching lines @@
   }
 };
 
 /**
  * This is a callback that gets called when the desktop size contained in the
  * the plugin has changed.
  *
  * @return {void} Nothing.
  */
 remoting.ClientSession.prototype.onDesktopSizeChanged_ = function() {
-  var width = this.plugin.desktopWidth;
-  var height = this.plugin.desktopHeight;
-  remoting.debug.log('desktop size changed: ' + width + 'x' + height);
-  this.plugin.width = width;
-  this.plugin.height = height;
+  remoting.debug.log('desktop size changed: ' +
+                     this.plugin.desktopWidth + 'x' +
+                     this.plugin.desktopHeight);
+  this.setScaleToFit(remoting.scaleToFit);
 };
 
 /**
  * Informs the plugin that it should scale itself.
  *
  * @param {boolean} shouldScale If the plugin should scale itself.
  * @return {void} Nothing.
  */
 remoting.ClientSession.prototype.setScaleToFit = function(shouldScale) {
   if (shouldScale) {
@@ skipping 18 matching lines @@
       remoting.debug.log('scale up is not supported');
       scale = 1.0;
     }
 
     this.plugin.width = this.plugin.desktopWidth * scale;
     this.plugin.height = this.plugin.desktopHeight * scale;
   } else {
     this.plugin.width = this.plugin.desktopWidth;
     this.plugin.height = this.plugin.desktopHeight;
   }
+
+  // Resize the plugin's container.  The container's style places its origin at
+  // the center of the page, so we use -ve margins to move that origin to the
+  // center of the container, rather than its top-left corner, so that it will
+  // appear centered on the page.
+  if (this.plugin.parentNode) {
+    var parentNode = this.plugin.parentNode;
+    parentNode.style["width"] = this.plugin.width + "px";
+    parentNode.style["height"] = this.plugin.height + "px";
+    parentNode.style["margin-left"] = -(this.plugin.width/2) + "px";
+    parentNode.style["margin-top"] = -(this.plugin.height/2) + "px";
+  }
+
   remoting.debug.log('plugin size is now: ' +
                      this.plugin.width + ' x ' + this.plugin.height + '.');
   this.plugin.setScaleToFit(shouldScale);
   remoting.debug.log('scale to fit is now: ' + shouldScale);
 };
 
 /**
  * Returns an associative array with a set of stats for this connection.
  *
  * @return {Object} The connection statistics.
  */
 remoting.ClientSession.prototype.stats = function() {
   return {
     'video_bandwidth': this.plugin.videoBandwidth,
     'capture_latency': this.plugin.videoCaptureLatency,
     'encode_latency': this.plugin.videoEncodeLatency,
     'decode_latency': this.plugin.videoDecodeLatency,
     'render_latency': this.plugin.videoRenderLatency,
     'roundtrip_latency': this.plugin.roundTripLatency
   };
 };
 
 }());