[REF][FIX] mail, im_livechat: various improvements (JS)

This commit makes a lot of small improvements of the JS of mail and
related modules.

	A. Mail Manager
	---------------

		im_support:

		- [REF] Slightly more robust way to determine a support
		        message, so that it more reliably falls back on
		        default kind of message (i.e. support channel UUID
		        should be clearly set).

		mail:

		- [REF] Improved method names for readability purposes.
		        Some examples:

		        - `fetchFromServer` becomes `fetchMailStateFromServer`
		        - `_initialize{*}` becomes `_update{*}FromServer`
		        - `_isModerator` becomes `_isMyselfModerator`

		- [REF] Use 'template' pattern design to make Include on
				Mail Manager much more robust. In particular,
				the flow is always as follow:

					1. Initialize internal state.
					2. Listen on buses.
					3. Fetch mail data from server.

		- [REF] Improved workflow for thread window workflow
		        (Shorter & more readable).

	B. Mail Tests
	-------------

		- [REF] Thread Window Tests crashes with clean message when
		        there are some thread windows open before running the
		        tests.

	C. (Model) Message
	------------------

		- [REF] Improved method names for readability purposes
				(e.g. `isAuthor` becomes `isMyselfAuthor`).

	D. (Model) Thread
	-----------------

		- [REF] Improved `init` parameters on each kind of thread.
		- [REF] 'Thread With Cache' has been renamed to 'Searchable
		        Thread': it embraces all kinds of threads that can
		        be used with the search view.
		- [REF] 'DM' has been renamed to 'DM Chat' (for clarity).
		- [IMP] New Livechat model in the backend.
		- [REF] No more direct instances of the Channel class: public
		        and private channels are now 'Multi-User' channels,
		        while DM Chat and Livechat are 'Two-User' channels:

		        This change has been made so that instances of classes
		        always have direct classes as "leaf" in the Class
		        modeling. It eases making changes to a certain model
		        without being too constrained by another model.

		- [REF] As a consequence of above changed, the method `isChat`
		        has been renamed to `isTwoUserThread`.

		        This is to avoid confusion with the terminology
		        'chat', which is more like a shortcut for 'quick real-
		        time conversation'. In other words, the property of
		        'chat' depends of the way to interact on a thread, not
		        of the intrinsic type of the thread.

		        Still, some parts have kept the terminology 'chat',
		        such as in the systray messagin menu.

		- [IMP] Added `message_added` and `message_posted` hooks,
		        which may be useful to easily hook on those events.

	E. Thread Widget
	----------------

		- [REF] Now uses a `mail.model.AbstractThread` for the
		        rendering of a thread, instead of a list of
		        `{mail.model.AbstractMessage}`.
		- [FIX] Stick thread scroll height to bottom on new rendering,
		        if it was previously at the bottom of the thread.
		- [REF] Option ORDER has its meaning changed: it now refers
		        to the chronological order of messages in the thread,
		        in which DESC means 'from top to bottom', while ASC
		        means 'from bottom to top'.
		- [REF] Improved doc on templates, in particular with the
	            option `ORDER`.

	F. Thread Window
	----------------

		- [REF] Moved more logic to thread windows, which were
		        previously in Mail Window Manager.
		- [REF] Now hides the thread widget attribute. So instead of
		        `threadWindow.threadWidget.isAtBottom()`, it uses
		        `threadWindow.isAtBottom()`.
		- [FIX] New received messages when not having focus on Odoo
		        tab should always make the corresponding thread
		        windows "passive" (i.e. windows that keep threads
		        unread until click on them).
		- [FIX] Blank thread window (i.e. 'New message' TW) correctly
		        opens Discuss with 'Inbox' when clicking on 'Expand'
		        Button in the title
		- [FIX] Do not display the composer for channels with property
		        'mass-mailing' set in thread windows.

	G. (Website) Livechat
	---------------------

		- [REF] Some `trigger` have been turned into `trigger_up`.
		- [REF] Some logic has been moved to models (e.g.
		        `{im_livechat.model.WebsiteLivechat}`), from
		        `{im_livechat.im_livechat.LivechatButton}`.
		- [FIX] New messages should be received in real-time. The
		        longpolling was broken with a recent refactoring on
		        bus service (6448420c5dd160470e465dee7729d19d8d5e7bab).

1 files changed, 1 insertions, 1 deletions

diff --git a/addons/mail/static/src/xml/abstract_thread_window.xml b/addons/mail/static/src/xml/abstract_thread_window.xml
index e62cdba042b..af72d5dd36c 100644
--- a/addons/mail/static/src/xml/abstract_thread_window.xml
+++ b/addons/mail/static/src/xml/abstract_thread_window.xml
@@ -15,7 +15,7 @@
             </div>
             <div class="o_thread_window_content">
             </div>
-            <div t-if='widget.hasThread()' class="o_thread_composer o_chat_mini_composer">
+            <div t-if="widget.needsComposer()" class="o_thread_composer o_chat_mini_composer">
                 <input class="o_composer_text_field" t-att-placeholder="widget.options.placeholder"/>
             </div>
         </div>