diff -r 000000000000 -r 6474c204b198 widget/gtk/nsColorPicker.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/widget/gtk/nsColorPicker.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,182 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <gtk/gtk.h>
+
+#include "nsColor.h"
+#include "nsColorPicker.h"
+#include "nsGtkUtils.h"
+#include "nsIWidget.h"
+#include "WidgetUtils.h"
+
+NS_IMPL_ISUPPORTS(nsColorPicker, nsIColorPicker)
+
+int nsColorPicker::convertGdkColorComponent(guint16 color_component) {
+  // GdkColor value is in range [0..65535]. We need something in range [0..255]
+  return (color_component * 255 + 127) / 65535;
+}
+
+guint16 nsColorPicker::convertToGdkColorComponent(int color_component) {
+  return color_component * 65535 / 255;
+}
+
+GdkColor nsColorPicker::convertToGdkColor(nscolor color) {
+  GdkColor result = { 0 /* obsolete, unused 'pixel' value */,
+      convertToGdkColorComponent(NS_GET_R(color)),
+      convertToGdkColorComponent(NS_GET_G(color)),
+      convertToGdkColorComponent(NS_GET_B(color)) };
+
+  return result;
+}
+
+GtkColorSelection* nsColorPicker::WidgetGetColorSelection(GtkWidget* widget)
+{
+  return GTK_COLOR_SELECTION(gtk_color_selection_dialog_get_color_selection(
+                             GTK_COLOR_SELECTION_DIALOG(widget)));
+}
+
+/* void init (in nsIDOMWindow parent, in AString title, in short mode); */
+NS_IMETHODIMP nsColorPicker::Init(nsIDOMWindow *parent,
+                                  const nsAString& title,
+                                  const nsAString& initialColor)
+{
+  mParentWidget = mozilla::widget::WidgetUtils::DOMWindowToWidget(parent);
+  mTitle = title;
+  mInitialColor = initialColor;
+
+  return NS_OK;
+}
+
+/* void open (in nsIColorPickerShownCallback aColorPickerShownCallback); */
+NS_IMETHODIMP nsColorPicker::Open(nsIColorPickerShownCallback *aColorPickerShownCallback)
+{
+
+  // Input color string should be 7 length (i.e. a string representing a valid
+  // simple color)
+  if (mInitialColor.Length() != 7) {
+    return NS_ERROR_FAILURE;
+  }
+
+  const nsAString& withoutHash  = StringTail(mInitialColor, 6);
+  nscolor color;
+  if (!NS_HexToRGB(withoutHash, &color)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  GdkColor color_gdk = convertToGdkColor(color);
+
+  if (mCallback) {
+    // It means Open has already been called: this is not allowed
+    NS_WARNING("mCallback is already set. Open called twice?");
+    return NS_ERROR_FAILURE;
+  }
+  mCallback = aColorPickerShownCallback;
+
+  nsXPIDLCString title;
+  title.Adopt(ToNewUTF8String(mTitle));
+  GtkWidget *color_chooser = gtk_color_selection_dialog_new(title);
+
+  GtkWindow *parent_window = GTK_WINDOW(mParentWidget->GetNativeData(NS_NATIVE_SHELLWIDGET));
+  if (parent_window) {
+    GtkWindow *window = GTK_WINDOW(color_chooser);
+    gtk_window_set_transient_for(window, parent_window);
+    gtk_window_set_destroy_with_parent(window, TRUE);
+  }
+
+  gtk_color_selection_set_current_color(WidgetGetColorSelection(color_chooser),
+                                        &color_gdk);
+
+  NS_ADDREF_THIS();
+  g_signal_connect(WidgetGetColorSelection(color_chooser), "color-changed",
+                   G_CALLBACK(OnColorChanged), this);
+  g_signal_connect(color_chooser, "response", G_CALLBACK(OnResponse), this);
+  g_signal_connect(color_chooser, "destroy", G_CALLBACK(OnDestroy), this);
+  gtk_widget_show(color_chooser);
+
+  return NS_OK;
+}
+
+/* static */ void
+nsColorPicker::OnColorChanged(GtkColorSelection* colorselection,
+                              gpointer user_data)
+{
+  static_cast<nsColorPicker*>(user_data)->Update(colorselection);
+}
+
+/* static */ void
+nsColorPicker::OnResponse(GtkWidget* color_chooser, gint response_id,
+                          gpointer user_data)
+{
+  static_cast<nsColorPicker*>(user_data)->
+    Done(color_chooser, response_id);
+}
+
+/* static */ void
+nsColorPicker::OnDestroy(GtkWidget* color_chooser, gpointer user_data)
+{
+  static_cast<nsColorPicker*>(user_data)->
+    Done(color_chooser, GTK_RESPONSE_CANCEL);
+}
+
+void
+nsColorPicker::Update(GtkColorSelection* colorselection)
+{
+  ReadValueFromColorSelection(colorselection);
+  if (mCallback) {
+    mCallback->Update(mColor);
+  }
+}
+
+void
+nsColorPicker::Done(GtkWidget* color_chooser, gint response)
+{
+  switch (response) {
+    case GTK_RESPONSE_OK:
+    case GTK_RESPONSE_ACCEPT:
+      ReadValueFromColorSelection(WidgetGetColorSelection(color_chooser));
+      break;
+    case GTK_RESPONSE_CANCEL:
+    case GTK_RESPONSE_CLOSE:
+    case GTK_RESPONSE_DELETE_EVENT:
+      mColor = mInitialColor;
+      break;
+    default:
+      NS_WARNING("Unexpected response");
+      break;
+  }
+
+  // A "response" signal won't be sent again but "destroy" will be.
+  g_signal_handlers_disconnect_by_func(color_chooser,
+                                       FuncToGpointer(OnDestroy), this);
+
+  gtk_widget_destroy(color_chooser);
+  if (mCallback) {
+    mCallback->Done(mColor);
+    mCallback = nullptr;
+  }
+
+  NS_RELEASE_THIS();
+}
+
+nsString nsColorPicker::ToHexString(int n)
+{
+  nsString result;
+  if (n <= 0x0F) {
+    result.Append('0');
+  }
+  result.AppendInt(n, 16);
+  return result;
+}
+
+void nsColorPicker::ReadValueFromColorSelection(GtkColorSelection* colorselection)
+{
+  GdkColor rgba;
+  gtk_color_selection_get_current_color(colorselection, &rgba);
+
+  mColor.AssignLiteral("#");
+  mColor += ToHexString(convertGdkColorComponent(rgba.red));
+  mColor += ToHexString(convertGdkColorComponent(rgba.green));
+  mColor += ToHexString(convertGdkColorComponent(rgba.blue));
+}