Fix residue left over from find bar when using accelerated compositing

chrome/browser/renderer_host/render_widget_host_view_win.cc

Index: chrome/browser/renderer_host/render_widget_host_view_win.cc
diff --git a/chrome/browser/renderer_host/render_widget_host_view_win.cc b/chrome/browser/renderer_host/render_widget_host_view_win.cc
index 407bc1d3c418727a58f42e1a1e2d9563efeefa03..f912d1a142688e92977408dc92dc4f6e4447fb3c 100644
--- a/chrome/browser/renderer_host/render_widget_host_view_win.cc
+++ b/chrome/browser/renderer_host/render_widget_host_view_win.cc
@@ -70,6 +70,8 @@ const wchar_t kRenderWidgetHostHWNDClass[] = L"Chrome_RenderWidgetHostHWND";
 
 namespace {
 
+const TCHAR* kRenderWidgetHVWPropStr = _T("RWHVW_P");
+
 // Tooltips will wrap after this width. Yes, wrap. Imagine that!
 const int kTooltipMaxWidthPixels = 300;
 
@@ -221,6 +223,7 @@ RenderWidgetHostView* RenderWidgetHostView::CreateViewForWidget(
 RenderWidgetHostViewWin::RenderWidgetHostViewWin(RenderWidgetHost* widget)
     : render_widget_host_(widget),
       compositor_host_window_(NULL),
+      was_compositing_just_scheduled_(false),
       hide_compositor_window_at_next_paint_(false),
       track_mouse_leave_(false),
       ime_notification_(false),
@@ -232,6 +235,7 @@ RenderWidgetHostViewWin::RenderWidgetHostViewWin(RenderWidgetHost* widget)
       tooltip_hwnd_(NULL),
       tooltip_showing_(false),
       shutdown_factory_(this),
+      method_factory_(this),
       parent_hwnd_(NULL),
       is_loading_(false),
       overlay_color_(0),
@@ -839,7 +843,7 @@ void RenderWidgetHostViewWin::OnPaint(HDC unused_dc) {
     // We initialize paint_dc here so that BeginPaint()/EndPaint()
     // get called to validate the region.
     CPaintDC paint_dc(m_hWnd);
-    render_widget_host_->ScheduleComposite();
+    ScheduleCompositeIfNeeded();
     return;
   }
 
@@ -1477,6 +1481,11 @@ static void PaintCompositorHostWindow(HWND hWnd) {
   PAINTSTRUCT paint;
   BeginPaint(hWnd, &paint);
 
+  RenderWidgetHostViewWin* win = static_cast<RenderWidgetHostViewWin*>(
+      GetProp(hWnd, kRenderWidgetHVWPropStr));
+  // May block unless parent window already did this.
+  win->ScheduleCompositeIfNeeded();
+
   EndPaint(hWnd, &paint);
 }
 
@@ -1488,6 +1497,7 @@ static LRESULT CALLBACK CompositorHostWindowProc(HWND hWnd, UINT message,
   case WM_ERASEBKGND:
     return 0;
   case WM_DESTROY:
+    RemoveProp(hWnd, kRenderWidgetHVWPropStr);
     return 0;
   case WM_PAINT:
     PaintCompositorHostWindow(hWnd);
@@ -1497,6 +1507,22 @@ static LRESULT CALLBACK CompositorHostWindowProc(HWND hWnd, UINT message,
   }
 }
 
+void RenderWidgetHostViewWin::ScheduleCompositeIfNeeded() {
+  // Call ScheduleComposite unless it has already occured during this set of
+  // Windows events.
+  if (!was_compositing_just_scheduled_) {
+    was_compositing_just_scheduled_ = true;
+    render_widget_host_->ScheduleComposite();
+    MessageLoop::current()->PostTask(FROM_HERE,

[darin (slow to review), 2011/05/26 23:03:06]

Maybe I don't understand what you are trying to accomplish, but won't
ResetWasCompositingJustScheduled be racing with receipt of the
ViewHostMsg_UpdateRect IPC?

RenderWidgetHost::ScheduleComposite will sometimes process
ViewHostMsg_UpdateRect before returning, but that is not guaranteed.

Maybe it would be helpful if I understood why you need to limit calls to
ScheduleComposite.

[jbates, 2011/05/27 17:11:41]

You're right - it's a mistake. The latest version is much simpler.

+        method_factory_.NewRunnableMethod(
+            &RenderWidgetHostViewWin::ResetWasCompositingJustScheduled));
+  }
+}
+
+void RenderWidgetHostViewWin::ResetWasCompositingJustScheduled() {
+  was_compositing_just_scheduled_ = false;
+}
+
 // Creates a HWND within the RenderWidgetHostView that will serve as a host
 // for a HWND that the GPU process will create. The host window is used
 // to Z-position the GPU's window relative to other plugin windows.
@@ -1537,6 +1563,8 @@ gfx::PluginWindowHandle RenderWidgetHostViewWin::GetCompositingSurface() {
     0, 0, width, height, m_hWnd, 0, GetModuleHandle(NULL), 0);
   ui::CheckWindowCreated(compositor_host_window_);
 
+  SetProp(compositor_host_window_, kRenderWidgetHVWPropStr, this);
+
   return static_cast<gfx::PluginWindowHandle>(compositor_host_window_);
 }