Use customized RGBA-enabled tooltip window for tooltip on ChroemOS

views/widget/tooltip_window_gtk.h

Index: views/widget/tooltip_window_gtk.h
diff --git a/views/widget/tooltip_window_gtk.h b/views/widget/tooltip_window_gtk.h
new file mode 100644
index 0000000000000000000000000000000000000000..556fa67f2a90f3d7477a1f492e5b6619795ca7a3
--- /dev/null
+++ b/views/widget/tooltip_window_gtk.h
@@ -0,0 +1,52 @@
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef VIEWS_WIDGET_TOOLTIP_WINDOW_GTK_H_
+#define VIEWS_WIDGET_TOOLTIP_WINDOW_GTK_H_
+
+#include <gtk/gtk.h>
+#include <string>
+
+#include "app/gtk_signal.h"
+
+namespace views {
+
+// TooltipWindowGtk provides a customized tooltip window and gives us a
+// chance to apply RGBA colormap on it. This enables the GTK theme engine to
+// draw tooltip with nice shadow and rounded corner on ChromeOS.
+class TooltipWindowGtk {
+ public:
+  explicit TooltipWindowGtk(GtkWidget* widget);
+  ~TooltipWindowGtk();
+
+  // Sets tooltip text to display.
+  void SetTooltipText(const std::wstring& text);
+
+  GtkLabel* label() {
+    return GTK_LABEL(label_);
+  }
+
+ protected:
+  CHROMEGTK_CALLBACK_1(TooltipWindowGtk, gboolean, OnPaint, GdkEventExpose*);
+  CHROMEGTK_CALLBACK_1(TooltipWindowGtk, void, OnStyleSet, GtkStyle*);
+
+ private:
+  void Init();
+
+  // Underlying widget of this tooltip window.
+  GtkWidget* host_;
+
+  // GtkWindow of this tooltip window.
+  GtkWidget* window_;
+
+  // The alignment and label widgets contained of the tooltip window.
+  GtkWidget* alignment_;
+  GtkWidget* label_;
+
+  DISALLOW_COPY_AND_ASSIGN(TooltipWindowGtk);
+};
+
+} // namespace views
+
+#endif  // VIEWS_WIDGET_TOOLTIP_WINDOW_GTK_H_