Only send unprocessed key events upwards if the RenderWidgetHost is not hidde...

chrome/browser/renderer_host/render_widget_host.cc

 // Copyright (c) 2010 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.
 
 #include "chrome/browser/renderer_host/render_widget_host.h"
 
 #include "base/auto_reset.h"
 #include "base/histogram.h"
 #include "base/keyboard_codes.h"
 #include "base/message_loop.h"
@@ skipping 998 matching lines @@
                << type << "). Ignoring event.";
 
     // Something must be wrong. Clear the |key_queue_| and
     // |suppress_next_char_events_| so that we can resume from the error.
     key_queue_.clear();
     suppress_next_char_events_ = false;
   } else {
     NativeWebKeyboardEvent front_item = key_queue_.front();
     key_queue_.pop_front();
 
-    if (!processed) {
+    // We only send unprocessed key event upwards if we are not hidden,
+    // because the user has moved away from us and no longer expect any effect
+    // of this key event.
+    if (!processed && !is_hidden_) {
       UnhandledKeyboardEvent(front_item);
 
       // WARNING: This RenderWidgetHost can be deallocated at this point
       // (i.e.  in the case of Ctrl+W, where the call to
       // UnhandledKeyboardEvent destroys this RenderWidgetHost).
     }
   }
 }