Diagnostics: Import all Polymer elements that have tests

Bug:1125150
Test: browser_tests --gtest_filter=DiagnosticsApp*

Change-Id: I15bdcec5d4737dcd5dba187b1b36346969e43edf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2429443
Commit-Queue: Michael Checo <michaelcheco@google.com>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810386}

chrome/test/data/webui/chromeos/diagnostics/diagnostics_test.js

@@ -4,7 +4,11 @@
 
 // TODO(jimmyxgong): Use es6 module for mojo binding (crbug/1004256).
 import 'chrome://resources/mojo/mojo/public/js/mojo_bindings_lite.js';
+import 'chrome://diagnostics/battery_status_card.js';
+import 'chrome://diagnostics/cpu_card.js';
 import 'chrome://diagnostics/diagnostics_app.js';
+import 'chrome://diagnostics/memory_card.js';
+import 'chrome://diagnostics/overview_card.js';
 
 import {SystemDataProviderInterface} from 'chrome://diagnostics/diagnostics_types.js';
 import {fakeBatteryChargeStatus, fakeBatteryHealth, fakeBatteryInfo, fakeCpuUsage, fakeMemoryUsage, fakeSystemInfo} from 'chrome://diagnostics/fake_data.js';