[geary/wip/765516-gtk-widget-conversation-viewer: 144/207] Fix massive memory leak due to some convo widgets never being freed.

[Michael Gratton <mjog src gnome org>]

commit 9953ef32356d43ffcb81e351d8b666640b4bbaa7
Author: Michael James Gratton <mike vee net>
Date:   Sun Aug 14 13:32:53 2016 +1000

    Fix massive memory leak due to some convo widgets never being freed.

 .../conversation-viewer/conversation-listbox.vala  |   10 +++++++++-
 .../conversation-viewer/conversation-viewer.vala   |   10 ++++------
 2 files changed, 13 insertions(+), 7 deletions(-)
---
diff --git a/src/client/conversation-viewer/conversation-listbox.vala 
b/src/client/conversation-viewer/conversation-listbox.vala
index 5179283..e5b829f 100644
--- a/src/client/conversation-viewer/conversation-listbox.vala
+++ b/src/client/conversation-viewer/conversation-listbox.vala
@@ -196,11 +196,19 @@ public class ConversationListBox : Gtk.ListBox {
     }
 
     ~ConversationListBox() {
+    public override void destroy() {
         this.cancellable.cancel();
         this.conversation.email_flags_changed.disconnect(on_update_flags);
         this.conversation.trimmed.disconnect(on_conversation_trimmed);
         this.conversation.appended.disconnect(on_conversation_appended);
-        get_adjustment().value_changed.disconnect(check_mark_read);
+        Gtk.Adjustment adjustment = get_adjustment();
+        if (adjustment != null) {
+            adjustment.value_changed.disconnect(check_mark_read);
+        }
+        this.body_selected_view = null;
+        this.last_email_row = null;
+        this.id_to_row.clear();
+        base.destroy();
     }
 
     public async void load_conversation()
diff --git a/src/client/conversation-viewer/conversation-viewer.vala 
b/src/client/conversation-viewer/conversation-viewer.vala
index fc3f61a..e98e8c9 100644
--- a/src/client/conversation-viewer/conversation-viewer.vala
+++ b/src/client/conversation-viewer/conversation-viewer.vala
@@ -287,16 +287,14 @@ public class ConversationViewer : Gtk.Stack {
 
     // Remove any existing conversation list, cancelling its loading
     private void remove_current_list() {
-        if (this.current_list != null) {
-            this.current_list.cancel_load();
-            this.conversation_removed(this.current_list);
-            this.current_list.destroy();
-            this.current_list = null;
-        }
         Gtk.Widget? scrolled_child = this.conversation_page.get_child();
         if (scrolled_child != null) {
             scrolled_child.destroy();
         }
+        if (this.current_list != null) {
+            this.conversation_removed(this.current_list);
+            this.current_list = null;
+        }
     }
 
     // State reset.