Implemented explicit resizing from guestview.

extensions/renderer/resources/guest_view/guest_view_container.js

Index: extensions/renderer/resources/guest_view/guest_view_container.js
diff --git a/extensions/renderer/resources/guest_view/guest_view_container.js b/extensions/renderer/resources/guest_view/guest_view_container.js
index 876b60623de0658eda154e87ca06920835bbb73f..6e909d8c5774c2f167c38fa1220216f96906cb4b 100644
--- a/extensions/renderer/resources/guest_view/guest_view_container.js
+++ b/extensions/renderer/resources/guest_view/guest_view_container.js
@@ -86,9 +86,13 @@ GuestViewContainer.prototype.attachWindow = function() {
     return true;
   }
 
-  this.guest.attach(this.internalInstanceId,
-                    this.viewInstanceId,
-                    this.buildAttachParams());
+  // Augment the attach parameters with the element size, so that the guestview
+  // can fit the element initially.
+  var attachParams = this.buildAttachParams();
+  attachParams['elementWidth'] = parseInt(this.element.style.width);
+  attachParams['elementHeight'] = parseInt(this.element.style.height);
+
+  this.guest.attach(this.internalInstanceId, this.viewInstanceId, attachParams);
   return true;
 };