Gtk3: Fix gn_all compile

remoting/host/disconnect_window_linux.cc

Index: remoting/host/disconnect_window_linux.cc
diff --git a/remoting/host/disconnect_window_linux.cc b/remoting/host/disconnect_window_linux.cc
index f79bd30dd3f8d07544ba36249f2aaf83edd1b572..f9f3b70e6a207669cc00058f53c6794568d961fd 100644
--- a/remoting/host/disconnect_window_linux.cc
+++ b/remoting/host/disconnect_window_linux.cc
@@ -54,6 +54,7 @@ class DisconnectWindowGtk : public HostWindow {
   DISALLOW_COPY_AND_ASSIGN(DisconnectWindowGtk);
 };
 
+#if GTK_MAJOR_VERSION == 2
 // Helper function for creating a rectangular path with rounded corners, as
 // Cairo doesn't have this facility.  |radius| is the arc-radius of each
 // corner.  The bounding rectangle extends from (0, 0) to (width, height).
@@ -66,6 +67,7 @@ void AddRoundRectPath(cairo_t* cairo_context, int width, int height,
   cairo_arc(cairo_context, radius, radius, radius, 2 * M_PI_2, 3 * M_PI_2);
   cairo_close_path(cairo_context);
 }
+#endif
 
 DisconnectWindowGtk::DisconnectWindowGtk()
     : disconnect_window_(nullptr),
@@ -138,7 +140,12 @@ void DisconnectWindowGtk::Start(
   gtk_alignment_set_padding(GTK_ALIGNMENT(align), 8, 8, 24, 12);
   gtk_container_add(GTK_CONTAINER(window), align);
 
+#if GTK_MAJOR_VERSION == 2
   GtkWidget* button_row = gtk_hbox_new(FALSE, 12);
+#else
+  GtkWidget* button_row = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 12);
+  gtk_box_set_homogeneous(GTK_BOX(button_row), FALSE);
+#endif
   gtk_container_add(GTK_CONTAINER(align), button_row);
 
   button_ = gtk_button_new_with_label(
@@ -197,6 +204,7 @@ gboolean DisconnectWindowGtk::OnConfigure(GtkWidget* widget,
   current_width_ = event->width;
   current_height_ = event->height;
 
+#if GTK_MAJOR_VERSION == 2

[Tom (Use chromium acct), 2017/02/01 00:02:42]

We can just let gtk draw the window background, right?

[Sergey Ulanov, 2017/02/02 00:42:49]

I don't think we want to omit this code. This code draws not only the
background, but also rounded corners, green border and gripper on the left. E.g.
here is the screenshot with GTK2:
https://drive.google.com/file/d/0B692SWJoRn0_cGszS09qakl0eEU/view?usp=sharing

   // Create the depth 1 pixmap for the window shape.
   GdkPixmap* shape_mask =
       gdk_pixmap_new(nullptr, current_width_, current_height_, 1);
@@ -270,6 +278,7 @@ gboolean DisconnectWindowGtk::OnConfigure(GtkWidget* widget,
   gdk_window_set_back_pixmap(widget->window, background, FALSE);
   g_object_unref(background);
   gdk_window_invalidate_rect(widget->window, nullptr, TRUE);
+#endif
 
   return FALSE;
 }