Hack around the floating tab when using space/enter to end a drag.

We don't get a drag-end or a drag-failed event if the user presses
space/enter, so we hack around this with a timer.  I filed a bug with
GTK+ upstream about not getting the event:
  https://bugzilla.gnome.org/show_bug.cgi?id=599130

BUG=21627

Review URL: http://codereview.chromium.org/300028

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@29697 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 38 insertions, 2 deletions

diff --git a/chrome/browser/gtk/tabs/tab_gtk.cc b/chrome/browser/gtk/tabs/tab_gtk.cc
index 251f04f..4713063 100644
--- a/chrome/browser/gtk/tabs/tab_gtk.cc
+++ b/chrome/browser/gtk/tabs/tab_gtk.cc
@@ -118,7 +118,8 @@ TabGtk::TabGtk(TabDelegate* delegate)
       last_mouse_down_(NULL),
       drag_widget_(NULL),
       title_width_(0),
-      ALLOW_THIS_IN_INITIALIZER_LIST(destroy_factory_(this)) {
+      ALLOW_THIS_IN_INITIALIZER_LIST(destroy_factory_(this)),
+      ALLOW_THIS_IN_INITIALIZER_LIST(drag_end_factory_(this)) {
   event_box_ = gtk_event_box_new();
   gtk_event_box_set_visible_window(GTK_EVENT_BOX(event_box_), FALSE);
   g_signal_connect(G_OBJECT(event_box_), "button-press-event",
@@ -219,6 +220,19 @@ gboolean TabGtk::OnDragFailed(GtkWidget* widget, GdkDragContext* context,
 }
 
 // static
+gboolean TabGtk::OnDragButtonReleased(GtkWidget* widget, GdkEventButton* button,
+                                      TabGtk* tab) {
+  // We always get this event when gtk is releasing the grab and ending the
+  // drag.  However, if the user ended the drag with space or enter, we don't
+  // get a follow up event to tell us the drag has finished (either a
+  // drag-failed or a drag-end).  So we post a task to manually end the drag.
+  // If GTK+ does send the drag-failed or drag-end event, we cancel the task.
+  MessageLoop::current()->PostTask(FROM_HERE,
+      tab->drag_end_factory_.NewRunnableMethod(&TabGtk::EndDrag, false));
+  return TRUE;
+}
+
+// static
 void TabGtk::OnDragBegin(GtkWidget* widget, GdkDragContext* context,
                          TabGtk* tab) {
   GdkPixbuf* pixbuf = gdk_pixbuf_new(GDK_COLORSPACE_RGB, TRUE, 8, 1, 1);
@@ -319,9 +333,12 @@ void TabGtk::UpdateTooltipState() {
 }
 
 void TabGtk::CreateDragWidget() {
+  DCHECK(!drag_widget_);
   drag_widget_ = gtk_invisible_new();
   g_signal_connect(drag_widget_, "drag-failed",
                    G_CALLBACK(OnDragFailed), this);
+  g_signal_connect(drag_widget_, "button-release-event",
+                   G_CALLBACK(OnDragButtonReleased), this);
   g_signal_connect_after(drag_widget_, "drag-begin",
                          G_CALLBACK(OnDragBegin), this);
 }
@@ -338,7 +355,7 @@ void TabGtk::StartDragging(gfx::Point drag_offset) {
 
   GtkTargetList* list = GtkDndUtil::GetTargetListFromCodeMask(
       GtkDndUtil::CHROME_TAB);
-  gtk_drag_begin(drag_widget_, list, GDK_ACTION_COPY,
+  gtk_drag_begin(drag_widget_, list, GDK_ACTION_MOVE,
                  1,  // Drags are always initiated by the left button.
                  last_mouse_down_);
 
@@ -346,6 +363,10 @@ void TabGtk::StartDragging(gfx::Point drag_offset) {
 }
 
 void TabGtk::EndDrag(bool canceled) {
+  // Make sure we only run EndDrag once by canceling any tasks that want
+  // to call EndDrag.
+  drag_end_factory_.RevokeAll();
+
   // We must let gtk clean up after we handle the drag operation, otherwise
   // there will be outstanding references to the drag widget when we try to
   // destroy it.
diff --git a/chrome/browser/gtk/tabs/tab_gtk.h b/chrome/browser/gtk/tabs/tab_gtk.h
index 5c3c662..c5a91d2 100644
--- a/chrome/browser/gtk/tabs/tab_gtk.h
+++ b/chrome/browser/gtk/tabs/tab_gtk.h
@@ -122,6 +122,14 @@ class TabGtk : public TabRendererGtk,
   static gboolean OnDragFailed(GtkWidget* widget, GdkDragContext* context,
                                GtkDragResult result, TabGtk* tab);
 
+  // When a drag is ending, a fake button release event is passed to the drag
+  // widget to fake letting go of the mouse button.  We need a callback for
+  // this event because it is the only way to catch drag end events when the
+  // user presses space or return.
+  static gboolean OnDragButtonReleased(GtkWidget* widget,
+                                       GdkEventButton* event,
+                                       TabGtk* tab);
+
   // Shows the context menu.
   void ShowContextMenu();
 
@@ -179,6 +187,13 @@ class TabGtk : public TabRendererGtk,
   // Used to destroy the drag widget after a return to the message loop.
   ScopedRunnableMethodFactory<TabGtk> destroy_factory_;
 
+  // Due to a bug in GTK+, we need to force the end of a drag when we get a
+  // mouse release event on the the dragged widget, otherwise, we don't know
+  // when the drag has ended when the user presses space or enter.  We queue
+  // a task to end the drag and only run it if GTK+ didn't send us the
+  // drag-failed event.
+  ScopedRunnableMethodFactory<TabGtk> drag_end_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(TabGtk);
 };