views: Amend trigger sequence for view_in_browser().

This makes MsgInfoView handle VIEW_IN_BROWSER keypress in order to avoid
too many/unintended triggers.

Tests amended and added.

tests/ui_tools/test_popups.py

@@ -504,8 +504,17 @@ def test_keypress_exit_popup(self, key, widget_size):
         self.msg_info_view.keypress(size, key)
         assert self.controller.exit_popup.called
 
+    @pytest.mark.parametrize('key', keys_for_command('VIEW_IN_BROWSER'))
+    def test_keypress_view_in_browser(self, widget_size, message_fixture, key):
+        size = widget_size(self.msg_info_view)
+
+        self.msg_info_view.keypress(size, key)
+
+        (self.controller.view_in_browser.
+         assert_called_once_with(message_fixture['id']))
+
     def test_height_noreactions(self):
-        expected_height = 3
+        expected_height = 4
         assert self.msg_info_view.height == expected_height
 
     # FIXME This is the same parametrize as MessageBox:test_reactions_view
@@ -553,8 +562,9 @@ def test_height_reactions(self, message_fixture, to_vary_in_each_message):
         self.msg_info_view = MsgInfoView(self.controller, varied_message,
                                          'Message Information', OrderedDict(),
                                          list())
-        # 9 = 3 labels + 1 blank line + 1 'Reactions' (category) + 4 reactions.
-        expected_height = 9
+        # 10 = 4 labels + 1 blank line + 1 'Reactions' (category) + 4
+        # reactions (excluding 'Message Links').
+        expected_height = 10
         assert self.msg_info_view.height == expected_height
 
     def test_keypress_navigation(self, mocker, widget_size,

zulipterminal/ui_tools/views.py

@@ -1232,7 +1232,10 @@ def __init__(self, controller: Any, msg: Message, title: str,
         msg_info = [
             ('', [('Date & Time', date_and_time),
                   ('Sender', msg['sender_full_name']),
-                  ('Sender\'s Email ID', msg['sender_email'])]),
+                  ('Sender\'s Email ID', msg['sender_email']),
+                  ('View message in the web browser', 'Press {}'.format(
+                   ', '.join(map(repr, keys_for_command('VIEW_IN_BROWSER'))))),
+                  ]),
         ]
         # Only show the 'Edit History' label for edited messages.
         self.show_edit_history_label = (
@@ -1303,6 +1306,8 @@ def keypress(self, size: urwid_Size, key: str) -> str:
                 message_links=self.message_links,
                 time_mentions=self.time_mentions,
             )
+        elif is_command_key('VIEW_IN_BROWSER', key):
+            self.controller.view_in_browser(self.msg['id'])
         return super().keypress(size, key)