hotkeys: Clean up dispatching of drafts hotkeys.

We now explicitly return true from process_hotkey() when we
handle up/down/backspace for the drafts modal.  Also, we no longer
call preventDefault() from drafts.draft_handle_events(), since the
caller does that, and we no longer return `true`, since we were
never inspecting the return value anyway.

frontend_tests/node_tests/hotkey.js

@@ -15,8 +15,6 @@ set_global('activity', {
 });
 
 set_global('drafts', {
-    drafts_handle_events: function () { return; },
-    drafts_overlay_open: function () { return; },
 });
 
 set_global('$', function () {
@@ -281,6 +279,7 @@ function stubbing(func_name_to_stub, test_function) {
 
     list_util.inside_list = return_false;
     global.current_msg_list.empty = return_true;
+    global.drafts.drafts_overlay_open = return_false;
     hotkey.is_settings_page = return_false;
     hotkey.is_subs = return_false;
 
@@ -331,4 +330,9 @@ function stubbing(func_name_to_stub, test_function) {
 
     assert_mapping('up_arrow', 'settings.handle_up_arrow');
     assert_mapping('down_arrow', 'settings.handle_down_arrow');
+
+    global.drafts.drafts_overlay_open = return_true;
+    assert_mapping('up_arrow', 'drafts.drafts_handle_events');
+    assert_mapping('down_arrow', 'drafts.drafts_handle_events');
+
 }());

static/js/drafts.js

@@ -260,10 +260,9 @@ exports.drafts_handle_events = function (e, event_key) {
                 // 55 is the minimum distance from the top that will require extra scrolling.
                 $(".drafts-list")[0].scrollTop = $(".drafts-list")[0].scrollTop - (55 - prev_focus_draft_row.position().top);
             }
-            e.preventDefault();
         }
-        return true;
     }
+
     // This detects down arrow key presses when the draft overlay
     // is open and scrolls through the drafts.
     if (event_key === "down_arrow") {
@@ -292,10 +291,9 @@ exports.drafts_handle_events = function (e, event_key) {
                     $(".drafts-list")[0].scrollTop = $(".drafts-list")[0].scrollTop + 2 - (dist_from_bottom);
                 }
             }
-            e.preventDefault();
         }
-        return true;
     }
+
     // Allows user to delete drafts with backspace
     if (event_key === "backspace") {
         var elt = document.activeElement;
@@ -319,8 +317,6 @@ exports.drafts_handle_events = function (e, event_key) {
             if ($("#drafts_table .draft-row").length === 0) {
                 $('#drafts_table .no-drafts').show();
             }
-            e.preventDefault();
-            return true;
         }
     }
 };

static/js/hotkey.js

@@ -432,8 +432,16 @@ exports.process_hotkey = function (e, hotkey) {
             return exports.process_escape_key(e);
     }
 
+    switch (event_name) {
+        // TODO: break out specific handlers for up_arrow,
+        //       down_arrow, and backspace
+        case 'up_arrow':
+        case 'down_arrow':
+        case 'backspace':
             if (drafts.drafts_overlay_open()) {
                 drafts.drafts_handle_events(e, event_name);
+                return true;
+            }
     }
 
     if (exports.is_settings_page()) {