Make a hole only as big as is necessary.

chrome/browser/renderer_host/render_widget_host_view_views.cc

Index: chrome/browser/renderer_host/render_widget_host_view_views.cc
diff --git a/chrome/browser/renderer_host/render_widget_host_view_views.cc b/chrome/browser/renderer_host/render_widget_host_view_views.cc
index c6be0b356c3060936e84e04db8411458451fd6e6..9d6bcc99dd201c26bb115d74fd53b25fca9097b5 100644
--- a/chrome/browser/renderer_host/render_widget_host_view_views.cc
+++ b/chrome/browser/renderer_host/render_widget_host_view_views.cc
@@ -282,6 +282,7 @@ void RenderWidgetHostViewViews::DidUpdateBackingStore(
     else
       SchedulePaint(rect, false);
   }
+  invalid_rect_ = invalid_rect_.Intersect(bounds());

[sadrul, 2011/01/21 16:36:19]

We need to either sanitize invalid_rect_ here, or sanitize paint_rect in ~390.

 }
 
 void RenderWidgetHostViewViews::RenderViewGone(base::TerminationStatus status,
@@ -358,7 +359,8 @@ void RenderWidgetHostViewViews::Paint(gfx::Canvas* canvas) {
   // Paint a "hole" in the canvas so that the render of the web page is on
   // top of whatever else has already been painted in the views hierarchy.
   // Later views might still get to paint on top.
-  canvas->FillRectInt(SK_ColorBLACK, 0, 0, kMaxWindowWidth, kMaxWindowHeight,
+  canvas->FillRectInt(SK_ColorBLACK, 0, 0,
+                      bounds().width(), bounds().height(),
                       SkXfermode::kClear_Mode);
 
   // Don't do any painting if the GPU process is rendering directly