Make context.call() call plugin actions correctly

In PolyGerrit, context.call() should will now use same context URL as in
GWT UI.

For change context:
/changes/project~changeid/pluginname~action

For revision context:
/changes/project~changeid/revisions/revisionid/pluginname~action

Feature: Issue 7685
Change-Id: I6db97ecdec9ab1f923148e2b65c8c347201f7ee3

polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.js

@@ -640,6 +640,9 @@
         // Plugin actions always contain ~ in the key.
         if (a.indexOf('~') !== -1) {
           pluginActions.push(actions[a]);
+          const patchNum = type === ActionType.REVISION ? this.patchNum : null;
+          this.$.restAPI.getChangeActionURL(this.changeNum, patchNum, '/' + a)
+              .then(url => actions[a].__url = url);
           // Add server-side provided plugin actions to overflow menu.
           this._overflowActions.push({
             type,

polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html

@@ -114,11 +114,32 @@ limitations under the License.
       assert.isFalse(element._shouldHideActions({base: ['test']}, false));
     });
 
-    test('plugin actions', () => {
+    test('plugin revision actions', () => {
+      sandbox.stub(element.$.restAPI, 'getChangeActionURL').returns(
+          Promise.resolve('the-url'));
       element.revisionActions = {
         'plugin~action': {},
       };
       assert.isOk(element.revisionActions['plugin~action']);
+      flush(() => {
+        assert.isTrue(element.$.restAPI.getChangeActionURL.calledWith(
+            element.changeNum, element.patchNum, '/plugin~action'));
+        assert.equal(element.revisionActions['plugin~action'].__url, 'the-url');
+      });
+    });
+
+    test('plugin change actions', () => {
+      sandbox.stub(element.$.restAPI, 'getChangeActionURL').returns(
+          Promise.resolve('the-url'));
+      element.actions = {
+        'plugin~action': {},
+      };
+      assert.isOk(element.actions['plugin~action']);
+      flush(() => {
+        assert.isTrue(element.$.restAPI.getChangeActionURL.calledWith(
+            element.changeNum, null, '/plugin~action'));
+        assert.equal(element.revisionActions['plugin~action'].__url, 'the-url');
+      });
     });
 
     test('not supported actions are filtered out', () => {

polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-action-context.js

@@ -79,9 +79,18 @@
     return this.div(checkbox, this.msg(title));
   };
 
+  GrPluginActionContext.prototype.prependLabel = function(title, checkbox) {
+    return this.label(checkbox, title);
+  };
+
   GrPluginActionContext.prototype.call = function(payload, onSuccess) {
-    this.plugin._send(
-        this.action.method, '/' + this.action.__key, onSuccess, payload);
+    if (!this.action.__url) {
+      console.warn(`Unable to ${this.action.method} to ${this.action.__key}!`);
+      return;
+    }
+    this.plugin.restApi()
+        .send(this.action.method, this.action.__url, payload)
+        .then(onSuccess);
   };
 
   window.GrPluginActionContext = GrPluginActionContext;

polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-action-context_test.html

@@ -115,13 +115,17 @@ limitations under the License.
       instance.action = {
         method: 'METHOD',
         __key: 'key',
+        __url: '/changes/1/revisions/2/foo~bar',
       };
-      sandbox.stub(plugin, '_send');
+      const sendStub = sandbox.stub().returns(Promise.resolve());
+      sandbox.stub(plugin, 'restApi').returns({
+        send: sendStub,
+      });
       const payload = {foo: 'foo'};
       const successStub = sandbox.stub();
       instance.call(payload, successStub);
-      assert.isTrue(
-          plugin._send.calledWith('METHOD', '/key', successStub, payload));
+      assert.isTrue(sendStub.calledWith(
+          'METHOD', '/changes/1/revisions/2/foo~bar', payload));
     });
   });
 </script>