[evolution] Bug 776224 - Workaround crash in WebKit on drag over preview

[Milan Crha <mcrha src gnome org>]

commit 3d5b60eb5dd52100ad55f19874f458efbbeba276
Author: Milan Crha <mcrha redhat com>
Date:   Tue Dec 20 15:00:00 2016 +0100

    Bug 776224 - Workaround crash in WebKit on drag over preview

 src/e-util/e-web-view.c |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)
---
diff --git a/src/e-util/e-web-view.c b/src/e-util/e-web-view.c
index 74f4131..b40c499 100644
--- a/src/e-util/e-web-view.c
+++ b/src/e-util/e-web-view.c
@@ -1268,10 +1268,35 @@ web_view_drag_motion (GtkWidget *widget,
                       gint y,
                       guint time_)
 {
+       /* Made this way to not pretend that this is a drop zone,
+          when only FALSE had been returned, even it is supposed
+          to be enough. Remove web_view_drag_leave() once fixed. */
+       gdk_drag_status (context, 0, time_);
+
+       return TRUE;
+}
+
+static gboolean
+web_view_drag_drop (GtkWidget *widget,
+                   GdkDragContext *context,
+                   gint x,
+                   gint y,
+                   guint time_)
+{
+       /* Defined to avoid crash in WebKit */
        return FALSE;
 }
 
 static void
+web_view_drag_leave (GtkWidget *widget,
+                    GdkDragContext *context,
+                    guint time_)
+{
+       /* Defined to avoid crash in WebKit, when the web_view_drag_motion()
+          uses the other way around. */
+}
+
+static void
 web_view_hovering_over_link (EWebView *web_view,
                              const gchar *title,
                              const gchar *uri)
@@ -2044,6 +2069,8 @@ e_web_view_class_init (EWebViewClass *class)
        widget_class = GTK_WIDGET_CLASS (class);
        widget_class->scroll_event = web_view_scroll_event;
        widget_class->drag_motion = web_view_drag_motion;
+       widget_class->drag_drop = web_view_drag_drop;
+       widget_class->drag_leave = web_view_drag_leave;
        widget_class->map = web_view_map;
        widget_class->unmap = web_view_unmap;