[evolution] EHTMLEditorView - Correct the situations when the 'Lose formatting' dialog is showed

[Tomas Popela <tpopela src gnome org>]

commit f934ef8e7611106bc10cec73175cf88d8731a6ed
Author: Tomas Popela <tpopela redhat com>
Date:   Wed Jun 29 13:23:57 2016 +0200

    EHTMLEditorView - Correct the situations when the 'Lose formatting' dialog is showed
    
    Don't show it when the message is a draft and show it when there are some of the
    HTML elements that does not belong to plain text mode.

 e-util/e-html-editor-view.c |   23 +++++++++++++++++++----
 1 files changed, 19 insertions(+), 4 deletions(-)
---
diff --git a/e-util/e-html-editor-view.c b/e-util/e-html-editor-view.c
index c9e9255..bbaa3be 100644
--- a/e-util/e-html-editor-view.c
+++ b/e-util/e-html-editor-view.c
@@ -11206,6 +11206,20 @@ toggle_unordered_lists (EHTMLEditorView *view)
        g_object_unref (list);
 }
 
+static gboolean
+needs_conversion (WebKitDOMDocument *document)
+{
+       WebKitDOMElement *element;
+
+       element = webkit_dom_document_query_selector (
+               document,
+               "b, i , u, table, hr, tt, font, sub, sup, h1, h2, h3, h4, h5, h6, "
+               "address, img:not([data-inline])",
+               NULL);
+
+       return element ? TRUE : FALSE;
+}
+
 /**
  * e_html_editor_view_set_html_mode:
  * @view: an #EHTMLEditorView
@@ -11229,6 +11243,9 @@ e_html_editor_view_set_html_mode (EHTMLEditorView *view,
 
        g_return_if_fail (E_IS_HTML_EDITOR_VIEW (view));
 
+       if (html_mode == view->priv->html_mode)
+               return;
+
        selection = e_html_editor_view_get_selection (view);
 
        document = webkit_web_view_get_dom_document (WEBKIT_WEB_VIEW (view));
@@ -11249,7 +11266,8 @@ e_html_editor_view_set_html_mode (EHTMLEditorView *view,
        convert = convert && !is_new_message;
 
        /* If toggling from HTML to plain text mode, ask user first */
-       if (convert && view->priv->html_mode && !html_mode) {
+       if (!html_mode && (needs_conversion (document) ||
+            (convert && !view->priv->is_message_from_draft))) {
                if (!show_lose_formatting_dialog (view))
                        return;
 
@@ -11262,9 +11280,6 @@ e_html_editor_view_set_html_mode (EHTMLEditorView *view,
                goto out;
        }
 
-       if (html_mode == view->priv->html_mode)
-               return;
-
        view->priv->html_mode = html_mode;
 
        /* Update fonts - in plain text we only want monospace */