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..7906219425a60c835aff939a927a1ab21182b06b 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 char* kRenderWidgetHVWPropStr = "RWHVW_P";

[nduca, 2011/05/25 23:42:29]

Chrome_RenderWidgetHostViewCompositorHWND_Parent

use const wchar_t and L prefix?

[jbates, 2011/05/26 18:21:16]

This string isn't actually used anywhere - only the pointer is used by windows
to be unique among other properties of the compositor window. I didn't want to
waste extra bytes of memory to make a descriptive string that is not used.

+
 // 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_completed_(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();
+    ScheduleComposite();
     return;
   }
 
@@ -1477,6 +1481,11 @@ static void PaintCompositorHostWindow(HWND hWnd) {
   PAINTSTRUCT paint;
   BeginPaint(hWnd, &paint);
 
+  RenderWidgetHostViewWin* win = static_cast<RenderWidgetHostViewWin*>(
+      GetPropA(hWnd, kRenderWidgetHVWPropStr));
+  // May block unless parent window already did this.
+  win->ScheduleComposite();
+
   EndPaint(hWnd, &paint);
 }
 
@@ -1488,6 +1497,7 @@ static LRESULT CALLBACK CompositorHostWindowProc(HWND hWnd, UINT message,
   case WM_ERASEBKGND:
     return 0;
   case WM_DESTROY:
+    RemovePropA(hWnd, kRenderWidgetHVWPropStr);

[nduca, 2011/05/25 23:42:29]

s/PropA/Prop if you use wchar as above

[jbates, 2011/05/26 18:21:16]

The MSDN example for SetProp uses char* strings and it turns out that it takes
char* or wchar* depending on compile flags. Rather than get into all that, I
decided to just be explicit with SetPropA since unicode precision is not an
issue.

Incidentally, you can specify _T("bla bla") to let the compiler decide (and that
matches the LPCTSTR type of SetProp). But I think that's a bit overkill for our
needs here.

     return 0;
   case WM_PAINT:
     PaintCompositorHostWindow(hWnd);
@@ -1497,6 +1507,20 @@ static LRESULT CALLBACK CompositorHostWindowProc(HWND hWnd, UINT message,
   }
 }
 
+void RenderWidgetHostViewWin::ScheduleComposite() {

[nduca, 2011/05/25 23:42:29]

ScheduleCompositeIfNotAlreadyDone?

A few words of what this code does might be good.

[vangelis, 2011/05/26 05:57:07]

I agree that a comment here would be needed.  I cannot tell what this code does
or how it fixes the issue.

[jbates, 2011/05/26 18:21:16]

Done.

+  if (!was_compositing_just_completed_) {
+    was_compositing_just_completed_ = true;
+    render_widget_host_->ScheduleComposite();
+    MessageLoop::current()->PostTask(FROM_HERE,
+        method_factory_.NewRunnableMethod(
+            &RenderWidgetHostViewWin::ResetWasCompositingJustCompleted));
+  }
+}
+
+void RenderWidgetHostViewWin::ResetWasCompositingJustCompleted() {
+  was_compositing_just_completed_ = 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 +1561,8 @@ gfx::PluginWindowHandle RenderWidgetHostViewWin::GetCompositingSurface() {
     0, 0, width, height, m_hWnd, 0, GetModuleHandle(NULL), 0);
   ui::CheckWindowCreated(compositor_host_window_);
 
+  SetPropA(compositor_host_window_, kRenderWidgetHVWPropStr, this);
+
   return static_cast<gfx::PluginWindowHandle>(compositor_host_window_);
 }