When DWM compositing is disabled (i.e. XP, RDP) ensure that windowed NPAPI plugins don't cover UI d…

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
===================================================================
--- content/browser/renderer_host/render_widget_host_view_aura.cc	(revision 234230)
+++ content/browser/renderer_host/render_widget_host_view_aura.cc	(working copy)
@@ -1253,6 +1253,8 @@
 #if defined(OS_WIN)
 void RenderWidgetHostViewAura::UpdateConstrainedWindowRects(
     const std::vector<gfx::Rect>& rects) {
+  if (rects == constrained_rects_)
+    return;
   constrained_rects_ = rects;
   UpdateCutoutRects();
 }