[FIX] web: prevent double translation in kanban view

The kanban view uses a template which comes from the server, already
translated.  Before this commit, it tried to retranslate again the
template in qweb.js, which may be a problem (in addition to the useless
work): if some english string A is translated in B (french), but B is
also a valid english string which is translated into C in french, then
we will have a wrong result.

In this commit, we simply add a flag to disable the translation process, which
should also slightly improve the kanban view rendering performance.

addons/web/static/src/js/core/qweb.js

@@ -5,7 +5,18 @@ var translation = require('web.translation');
 
 var _t = translation._t;
 
-function QWeb(debug, default_dict) {
+/**
+ * @param {boolean} debug
+ * @param {Object} default_dict
+ * @param {boolean} [enableTranslation=true] if true (this is the default),
+ *   the rendering will translate all strings that are not marked with
+ *   t-translation=off.  This is useful for the kanban view, which uses a
+ *   template which is already translated by the server
+ */
+function QWeb(debug, default_dict, enableTranslation) {
+    if (enableTranslation === undefined) {
+        enableTranslation = true;
+    }
     var qweb = new QWeb2.Engine();
     qweb.default_dict = _.extend({}, default_dict || {}, {
         '_' : _,
@@ -16,7 +27,7 @@ function QWeb(debug, default_dict) {
         'csrf_token': odoo.csrf_token,
     });
     qweb.debug = debug;
-    qweb.preprocess_node = preprocess_node;
+    qweb.preprocess_node = enableTranslation ? preprocess_node : function () {};
     return qweb;
 }
 

addons/web/static/src/js/views/kanban/kanban_renderer.js

@@ -94,7 +94,7 @@ var KanbanRenderer = BasicRenderer.extend({
         this._super.apply(this, arguments);
 
         this.widgets = [];
-        this.qweb = new QWeb(session.debug, {_s: session.origin});
+        this.qweb = new QWeb(session.debug, {_s: session.origin}, false);
         var templates = findInNode(this.arch, function (n) { return n.tag === 'templates';});
         transformQwebTemplate(templates, state.fields);
         this.qweb.add_template(utils.json_node_to_xml(templates));