Fix problems correctly invalidating/repainting when our updated paint rect fo...

chrome/browser/renderer_host/render_widget_host_view_win.cc

 // Copyright (c) 2006-2008 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_win.h"
 
 #include "base/command_line.h"
 #include "base/gfx/gdi_util.h"
 #include "base/gfx/rect.h"
 #include "base/histogram.h"
@@ skipping 116 matching lines @@
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewWin, public:
 
 RenderWidgetHostViewWin::RenderWidgetHostViewWin(RenderWidgetHost* widget)
     : render_widget_host_(widget),
       track_mouse_leave_(false),
       ime_notification_(false),
       is_hidden_(false),
+      about_to_validate_and_paint_(false),
       close_on_deactivate_(false),
       tooltip_hwnd_(NULL),
       tooltip_showing_(false),
       shutdown_factory_(this),
       parent_hwnd_(NULL),
       is_loading_(false) {
   render_widget_host_->set_view(this);
   renderer_accessible_ =
       CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableRendererAccessibility);
@@ skipping 293 matching lines @@
         bitmap->height(), NULL);
     if (rtl_dir)
       canvas.restore();
   }
 }
 
 void RenderWidgetHostViewWin::DidPaintRect(const gfx::Rect& rect) {
   if (is_hidden_)
     return;
 
-  Redraw(rect);
+  if (about_to_validate_and_paint_)
+    InvalidateRect(&rect.ToRECT(), false);
+  else
+    Redraw(rect);
 }
 
 void RenderWidgetHostViewWin::DidScrollRect(
     const gfx::Rect& rect, int dx, int dy) {
   if (is_hidden_)
     return;
 
   // We need to pass in SW_INVALIDATE to ScrollWindowEx.  The MSDN
   // documentation states that it only applies to the HRGN argument, which is
   // wrong.  Not passing in this flag does not invalidate the region which was
@@ skipping 84 matching lines @@
   ResetTooltip();
   TrackMouseLeave(false);
 #ifdef ENABLE_TRACK_HWND_DESTRUCTION
   TRACK_HWND_DESTRUCTION(m_hWnd);
 #endif //  ENABLE_TRACK_HWND_DESTRUCTION
 }
 
 void RenderWidgetHostViewWin::OnPaint(HDC dc) {
   DCHECK(render_widget_host_->process()->channel());
 
-  CPaintDC paint_dc(m_hWnd);
-  HBRUSH white_brush = reinterpret_cast<HBRUSH>(GetStockObject(WHITE_BRUSH));
-
+  about_to_validate_and_paint_ = true;
   BackingStore* backing_store = render_widget_host_->GetBackingStore();
 
+  // We initialize |paint_dc| (and thus call BeginPaint()) after calling
+  // GetBackingStore(), so that if it updates the invalid rect we'll catch the
+  // changes and repaint them.
+  about_to_validate_and_paint_ = false;
+  CPaintDC paint_dc(m_hWnd);
+
+  HBRUSH white_brush = reinterpret_cast<HBRUSH>(GetStockObject(WHITE_BRUSH));
   if (backing_store) {
     gfx::Rect damaged_rect(paint_dc.m_ps.rcPaint);
 
     gfx::Rect bitmap_rect(
         0, 0, backing_store->size().width(), backing_store->size().height());
 
     gfx::Rect paint_rect = bitmap_rect.Intersect(damaged_rect);
     if (!paint_rect.IsEmpty()) {
       DrawResizeCorner(paint_rect, backing_store->hdc());
       BitBlt(paint_dc.m_hDC,
@@ skipping 575 matching lines @@
     // WM_LBUTTONDOWN.
     SetFocus();
   }
 }
 
 void RenderWidgetHostViewWin::ShutdownHost() {
   shutdown_factory_.RevokeAll();
   render_widget_host_->Shutdown();
   // Do not touch any members at this point, |this| has been deleted.
 }