Fix bug with drop arrow updating on the tabstrip. See comment in widget_win.cc

http://crbug.com/74764
TEST=none

Review URL: http://codereview.chromium.org/6665050

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@78545 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 16 insertions, 3 deletions

diff --git a/views/widget/widget_win.cc b/views/widget/widget_win.cc
index d39f767..2c247fd 100644
--- a/views/widget/widget_win.cc
+++ b/views/widget/widget_win.cc
@@ -136,6 +136,7 @@ WidgetWin::WidgetWin()
       active_mouse_tracking_flags_(0),
       use_layered_buffer_(false),
       layered_alpha_(255),
+      ALLOW_THIS_IN_INITIALIZER_LIST(paint_layered_window_factory_(this)),
       delete_on_destroy_(true),
       can_update_layered_window_(true),
       last_mouse_event_was_move_(false),
@@ -397,6 +398,17 @@ void WidgetWin::SchedulePaintInRect(const gfx::Rect& rect) {
     // We must update the back-buffer immediately, since Windows' handling of
     // invalid rects is somewhat mysterious.
     layered_window_invalid_rect_ = layered_window_invalid_rect_.Union(rect);
+
+    // In some situations, such as drag and drop, when Windows itself runs a
+    // nested message loop our message loop appears to be starved and we don't
+    // receive calls to DidProcessMessage(). This only seems to affect layered
+    // windows, so we schedule a redraw manually using a task, since those never
+    // seem to be starved. Also, wtf.
+    if (paint_layered_window_factory_.empty()) {
+      MessageLoop::current()->PostTask(FROM_HERE,
+          paint_layered_window_factory_.NewRunnableMethod(
+          &WidgetWin::RedrawLayeredWindowContents));
+    }
   } else {
     // InvalidateRect() expects client coordinates.
     RECT r = rect.ToRECT();
@@ -1081,9 +1093,7 @@ void WidgetWin::MakeMSG(MSG* msg, UINT message, WPARAM w_param, LPARAM l_param,
 }
 
 void WidgetWin::RedrawInvalidRect() {
-  if (use_layered_buffer_) {
-    RedrawLayeredWindowContents();
-  } else {
+  if (!use_layered_buffer_) {
     RECT r = { 0, 0, 0, 0 };
     if (GetUpdateRect(hwnd(), &r, FALSE) && !IsRectEmpty(&r)) {
       RedrawWindow(hwnd(), &r, NULL,
diff --git a/views/widget/widget_win.h b/views/widget/widget_win.h
index 47863c7..2428a3e8 100644
--- a/views/widget/widget_win.h
+++ b/views/widget/widget_win.h
@@ -490,6 +490,9 @@ class WidgetWin : public ui::WindowImpl,
   // (In fact, it'll return misleading information from GetUpdateRect()).
   gfx::Rect layered_window_invalid_rect_;
 
+  // A factory that allows us to schedule a redraw for layered windows.
+  ScopedRunnableMethodFactory<WidgetWin> paint_layered_window_factory_;
+
   // Whether or not the window should delete itself when it is destroyed.
   // Set this to false via its setter for stack allocated instances.
   bool delete_on_destroy_;