Add a setNeedsLayout method to WebPluginContainer.

public/web/WebPluginContainer.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2014 Opera Software ASA. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 45 matching lines @@
         TouchEventRequestTypeSynthesizedMouse,
     };
 
     // Returns the element containing this plugin.
     virtual WebElement element() = 0;
 
     virtual void invalidate() = 0;
     virtual void invalidateRect(const WebRect&) = 0;
     virtual void scrollRect(const WebRect&) = 0;
 
+    // Causes the container to be marked as needing layout, which in turn will cause
+    // layoutIfNeeded() to be called on any contained WebPlugin during the container's
+    // web view's lifecycle update, and in particular before calling paint() on the
+    // WebPlugin.
+    virtual void setNeedsLayout() = 0;
+
     // Causes the container to report its current geometry via
     // WebPlugin::updateGeometry.
     virtual void reportGeometry() = 0;
 
     // Allow the plugin to pass script objects to the browser. The container
     // tracks ownership of script objects in order to allow browser references
     // to them to be dropped when clearScriptObjects is called.
     virtual void allowScriptObjects() = 0;
 
     // Drop any references to script objects allocated by the plugin.
@@ skipping 58 matching lines @@
     // WebPluginContainer does *not* take ownership.
     virtual void setWebLayer(WebLayer*) = 0;
 
 protected:
     ~WebPluginContainer() { }
 };
 
 } // namespace blink
 
 #endif