Worked around infinite loop seen in Chrome on Windows when raising and...

plugin/win/main_win.cc

Index: plugin/win/main_win.cc
===================================================================
--- plugin/win/main_win.cc	(revision 19991)
+++ plugin/win/main_win.cc	(working copy)
@@ -472,6 +472,10 @@
   switch (Msg) {
     case WM_PAINT: {
       if (reentrance_count.get() > 1) {
+        // In Chrome, alert dialogs raised from JavaScript cause
+        // reentrant WM_PAINT messages to be dispatched and 100% CPU
+        // to be consumed unless we call this
+        ::ValidateRect(hWnd, NULL);
         break;  // Ignore this message; we're reentrant.
       }
       PAINTSTRUCT paint_struct;