[epiphany] find-toolbar: Correctly handle zero matches

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 1a9108f334b3a08ac52b54a18520111f13c700f8
Author: Dimitrios Christidis <dimitrios christidis me>
Date:   Sun Nov 3 19:34:05 2019 +0100

    find-toolbar: Correctly handle zero matches
    
    Fixes: https://gitlab.gnome.org/GNOME/epiphany/issues/984

 embed/ephy-find-toolbar.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)
---
diff --git a/embed/ephy-find-toolbar.c b/embed/ephy-find-toolbar.c
index 61b45aed2..b850183ed 100644
--- a/embed/ephy-find-toolbar.c
+++ b/embed/ephy-find-toolbar.c
@@ -598,18 +598,24 @@ ephy_find_toolbar_set_web_view (EphyFindToolbar *toolbar,
 void
 ephy_find_toolbar_find_next (EphyFindToolbar *toolbar)
 {
-  toolbar->current_match++;
-  if (toolbar->current_match > toolbar->num_matches)
-    toolbar->current_match = 1;
+  if (toolbar->num_matches) {
+    toolbar->current_match++;
+    if (toolbar->current_match > toolbar->num_matches)
+      toolbar->current_match = 1;
+  }
+
   webkit_find_controller_search_next (toolbar->controller);
 }
 
 void
 ephy_find_toolbar_find_previous (EphyFindToolbar *toolbar)
 {
-  toolbar->current_match--;
-  if (toolbar->current_match < 1)
-    toolbar->current_match = toolbar->num_matches;
+  if (toolbar->num_matches) {
+    g_assert (toolbar->current_match > 0);
+    toolbar->current_match--;
+    if (toolbar->current_match < 1)
+      toolbar->current_match = toolbar->num_matches;
+  }
 
   webkit_find_controller_search_previous (toolbar->controller);
 }