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 3318d7b16702a277982c6ad635089abbc15a13e8..e5e7fe65ea1e54a88175b57484fa580b18425996 100644
--- a/extensions/renderer/resources/guest_view/guest_view_container.js
+++ b/extensions/renderer/resources/guest_view/guest_view_container.js
@@ -82,14 +82,22 @@ GuestViewContainer.prototype.setupFocusPropagation = function() {
   }.bind(this));
 };
 
+GuestViewContainer.prototype.attach = function() {
+  // 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.offsetWidth);
+  attachParams['elementHeight'] = parseInt(this.element.offsetHeight);
+
+  this.guest.attach(this.internalInstanceId, this.viewInstanceId, attachParams);
+};
+
 GuestViewContainer.prototype.attachWindow = function() {
   if (!this.internalInstanceId) {
     return true;
   }
 
-  this.guest.attach(this.internalInstanceId,
-                    this.viewInstanceId,
-                    this.buildAttachParams());
+  this.attach();
   return true;
 };
 
@@ -106,9 +114,7 @@ GuestViewContainer.prototype.handleBrowserPluginAttributeMutation =
     if (!this.guest.getId()) {
       return;
     }
-    this.guest.attach(this.internalInstanceId,
-                      this.viewInstanceId,
-                      this.buildAttachParams());
+    this.attach();
   }
 };