Make a hole only as big as is necessary.

chrome/browser/renderer_host/render_widget_host_view_views.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_view_views.h"
 
 #include <algorithm>
 #include <string>
 
 #include "app/l10n_util.h"
@@ skipping 264 matching lines @@
     // Paint(scroll_rect) above.
     gfx::Rect rect = copy_rects[i].Subtract(scroll_rect);
     if (rect.IsEmpty())
       continue;
 
     if (about_to_validate_and_paint_)
       invalid_rect_ = invalid_rect_.Union(rect);
     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,
                                                int error_code) {
   GetRenderWidgetHost()->ViewDestroyed();
   Destroy();
 }
 
 void RenderWidgetHostViewViews::Destroy() {
   // host_'s destruction brought us here, null it out so we don't use it
@@ skipping 56 matching lines @@
 }
 
 void RenderWidgetHostViewViews::Paint(gfx::Canvas* canvas) {
   if (is_hidden_) {
     return;
   }
 
   // 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
   // into the View.
   RenderWidgetHost* render_widget_host = GetRenderWidgetHost();
   if (render_widget_host->is_accelerated_compositing_active()) {
     return;
   }
 
   GdkWindow* window = GetInnerNativeView()->window;
@@ skipping 394 matching lines @@
 }
 
 // static
 RenderWidgetHostView*
     RenderWidgetHostView::GetRenderWidgetHostViewFromNativeView(
         gfx::NativeView widget) {
   gpointer user_data = g_object_get_data(G_OBJECT(widget),
                                          kRenderWidgetHostViewKey);
   return reinterpret_cast<RenderWidgetHostView*>(user_data);
 }