Clear the clipboard closing Incognito window

ui/base/clipboard/clipboard_gtk.cc

Index: ui/base/clipboard/clipboard_gtk.cc
diff --git a/ui/base/clipboard/clipboard_gtk.cc b/ui/base/clipboard/clipboard_gtk.cc
index 7473f31097289eb0b7bc716711c256392a2fd88f..74a94db08e5e05c0a1d039ec003d934d74261703 100644
--- a/ui/base/clipboard/clipboard_gtk.cc
+++ b/ui/base/clipboard/clipboard_gtk.cc
@@ -110,6 +110,7 @@ const char kMimeTypeBitmap[] = "image/bmp";
 const char kMimeTypeMozillaURL[] = "text/x-moz-url";
 const char kMimeTypePepperCustomData[] = "chromium/x-pepper-custom-data";
 const char kMimeTypeWebkitSmartPaste[] = "chromium/x-webkit-paste";
+const char kIncognitoMarkerType[] = "org.chromium.incognito-marker";
 
 std::string GdkAtomToString(const GdkAtom& atom) {
   gchar* name = gdk_atom_name(atom);
@@ -217,7 +218,7 @@ Clipboard::~Clipboard() {
   gtk_clipboard_store(clipboard_);
 }
 
-void Clipboard::WriteObjects(Buffer buffer, const ObjectMap& objects) {
+void Clipboard::WriteObjectsImpl(Buffer buffer, const ObjectMap& objects) {
   DCHECK(CalledOnValidThread());
   clipboard_data_ = new TargetMap();
 
@@ -659,6 +660,12 @@ const Clipboard::FormatType& Clipboard::GetPepperCustomDataFormatType() {
   return type;
 }
 
+// static
+const Clipboard::FormatType& Clipboard::GetIncognitoMarkerFormatType() {
+  CR_DEFINE_STATIC_LOCAL(FormatType, type, (kIncognitoMarkerType));
+  return type;
+}
+
 void Clipboard::InsertMapping(const char* key,
                               char* data,
                               size_t data_len) {