Don't send mouse events if the plugin doesn't have focus.

remoting/webapp/client_session.js

Index: remoting/webapp/client_session.js
diff --git a/remoting/webapp/client_session.js b/remoting/webapp/client_session.js
index 3a78b4e3ccdce11b1a94f414ad21953249e7b753..79aeae2260760793128910145320a4a5979ba61e 100644
--- a/remoting/webapp/client_session.js
+++ b/remoting/webapp/client_session.js
@@ -348,7 +348,11 @@ remoting.ClientSession.prototype.pluginLostFocus_ = function() {
     this.plugin_.releaseAllKeys();
     if (this.plugin_.element()) {
       // Focus should stay on the element, not (for example) the toolbar.
-      this.plugin_.element().focus();
+      // Due to crbug.com/246335, we can't restore the focus immediately,
+      // otherwise the plugin gets confused about whether or not it has focus.
+      window.setTimeout(
+          this.plugin_.element().focus.bind(this.plugin_.element()),
+          0);

[weitao, 2014/02/07 23:54:23]

Nice trick. :)

     }
   }
 };