PolyGerrit: Reduce the threshold in gr-watched-projects-editor

Reducing the threshold to 1 allows for more aggressive autocomplete
results, and also supports project names with less than three
characters.

Bug: Issue 7520
Change-Id: I7a97be7312806e5ba12bbc6e022ffa05741a2fe7
(cherry picked from commit cd63eb511af53374425ae55672a2155fadb50d65)
diff --git a/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.html b/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.html
index 68b2c23..cf5e0b1 100644
--- a/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.html
+++ b/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.html
@@ -96,7 +96,7 @@
               <gr-autocomplete
                   id="newProject"
                   query="[[_query]]"
-                  threshold="3"
+                  threshold="1"
                   placeholder="Project"></gr-autocomplete>
             </th>
             <th colspan$="[[_getTypeCount()]]">
diff --git a/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor_test.html b/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor_test.html
index a93beb1..fbc6217 100644
--- a/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor_test.html
+++ b/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor_test.html
@@ -58,7 +58,7 @@
 
       stub('gr-rest-api-interface', {
         getSuggestedProjects(input) {
-          if (input.startsWith('the')) {
+          if (input.startsWith('th')) {
             return Promise.resolve({'the project': {
               id: 'the project',
               state: 'ACTIVE',
@@ -122,6 +122,14 @@
       });
     });
 
+    test('_getProjectSuggestions non-empty with two letter project', done => {
+      element._getProjectSuggestions('th').then(projects => {
+        assert.equal(projects.length, 1);
+        assert.equal(projects[0].name, 'the project');
+        done();
+      });
+    });
+
     test('_canAddProject', () => {
       assert.isFalse(element._canAddProject(null, null));
       assert.isFalse(element._canAddProject({}, null));