Refresh auth credentials prospective fixes

- Initial credentials refresh right after auth error to clear cache and
  to handle situation of auth error because of stale auth cookie.
- Clear REST API cache entirely to remove all auth-dependent data.

Bug: Issue 4285
Change-Id: I310ac9443ddd46c15d3c34c32d843a0af6db50df

polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager.js

@@ -100,6 +100,9 @@
         this.listen(document, 'visibilitychange', '_handleVisibilityChange');
       }
       this._requestCheckLoggedIn();
+      if (!document.hidden) {
+        this._handleVisibilityChange();
+      }
     },
 
     _createToastAlert: function() {

polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager_test.html

@@ -105,7 +105,7 @@ limitations under the License.
 
         var hideToastSpy = sandbox.spy(toast, 'hide');
 
-        assert.isFalse(refreshStub.called);
+        assert.isTrue(refreshStub.called);
         element.flushDebouncer('checkLoggedIn');
         flush(function() {
           assert.isTrue(refreshStub.called);

polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js

@@ -251,7 +251,7 @@
     },
 
     refreshCredentials: function() {
-      this._cache['/accounts/self/detail'] = undefined;
+      this._cache = {};
       return this.getLoggedIn();
     },