[FIX] web: give context to fetch x2m batched

Before this commit M2Mtags widget did not translate.
This was because no context was given to the rpc that fetched the fields
Hence, the lang was not passed.

After this commit, M2Mtags translate well

OPW 784396

addons/web/static/src/js/views/basic/basic_model.js

@@ -1480,7 +1480,8 @@ var BasicModel = AbstractModel.extend({
                     def = this._rpc({
                         model: list.model,
                         method: 'read',
-                        args: [_.pluck(data, 'id'), fieldNames]
+                        args: [_.pluck(data, 'id'), fieldNames],
+                        context: record.context,
                     }).then(function (records) {
                         _.each(records, function (record) {
                             list_records[record.id].data = record;
@@ -2399,7 +2400,7 @@ var BasicModel = AbstractModel.extend({
                 model: field.relation,
                 method: 'read',
                 args: [ids, fieldNames],
-                context: {}, // FIXME
+                context: list.getContext() || {},
             });
         } else {
             def = $.when(_.map(ids, function (id) {

addons/web/static/tests/fields/relational_fields_tests.js

@@ -8055,7 +8055,7 @@ QUnit.module('relational_fields', {
     });
 
     QUnit.test('fieldmany2many tags in editable list', function (assert) {
-        assert.expect(4);
+        assert.expect(7);
 
         this.data.partner.records[0].timmy = [12];
 
@@ -8063,10 +8063,18 @@ QUnit.module('relational_fields', {
             View: ListView,
             model: 'partner',
             data: this.data,
+            context: {take: 'five'},
             arch:'<tree editable="bottom">' +
                     '<field name="foo"/>' +
                     '<field name="timmy" widget="many2many_tags"/>' +
                 '</tree>',
+            mockRPC: function (route, args) {
+                if (args.method === 'read' && args.model === 'partner_type') {
+                    assert.deepEqual(args.kwargs.context, {take: 'five'},
+                        'The context should be passed to the RPC');
+                }
+            return this._super.apply(this, arguments);
+            }
         });
 
         assert.strictEqual(list.$('.o_data_row:first .o_field_many2manytags .badge').length, 1,