function triggerUpdateLayout(refreshHint) {
        // Find how much space is left for the editor
        var editorAreaHeight = calcAvailableHeight();

        $editorHolder.height(editorAreaHeight);  // affects size of "not-editor" placeholder as well

        // Resize editor to fill the space
        exports.trigger(EVENT_WORKSPACE_UPDATE_LAYOUT, editorAreaHeight, refreshHint);
    }
Calculates a new size for editor-holder and resizes it accordingly, then and dispatches the "workspaceUpdateLayout"
event. (The editors within are resized by EditorManager, in response to that event).

@param {boolean=} refreshHint  true to force a complete refresh