[Android Tests] Fix notification channel tests that only run on O

- Some of these tests were consistently failing but went unnoticed
because they only run on Android O+ and there are no cq-blocking
O bots yet.

- Tested by running all tests with *Channels* in the name on an
Android O device.

Change-Id: I29d92984eb9f9d74062ec36dc391412be8b0fa51
Reviewed-on: https://chromium-review.googlesource.com/1158834Reviewed-by: Peter Beverloo <peter@chromium.org>
Commit-Queue: Anita Woodruff <awdf@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579852}

chrome/android/javatests/src/org/chromium/chrome/browser/notifications/channels/ChannelsUpdaterTest.java

@@ -159,6 +159,9 @@ public class ChannelsUpdaterTest {
     @TargetApi(Build.VERSION_CODES.O)
     public void testUpdateChannels_deletesLegacyChannelsAndCreatesExpectedOnes() throws Exception {
         // Set up any legacy channels.
+        mNotificationManagerProxy.createNotificationChannelGroup(
+                ChannelDefinitions.getChannelGroup(ChannelDefinitions.ChannelGroupId.GENERAL)
+                        .toNotificationChannelGroup(mMockResources));
         for (String id : ChannelDefinitions.getLegacyChannelIds()) {
             NotificationChannel channel =
                     new NotificationChannel(id, id, NotificationManager.IMPORTANCE_LOW);

chrome/android/javatests/src/org/chromium/chrome/browser/notifications/channels/SiteChannelsManagerTest.java

@@ -33,7 +33,7 @@ import org.chromium.chrome.browser.notifications.NotificationManagerProxyImpl;
 import org.chromium.chrome.browser.notifications.NotificationSettingsBridge;
 import org.chromium.chrome.browser.preferences.website.ContentSetting;
 import org.chromium.chrome.browser.preferences.website.PermissionInfo;
-import org.chromium.content.browser.test.NativeLibraryTestRule;
+import org.chromium.chrome.browser.test.ChromeBrowserTestRule;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -53,11 +53,11 @@ import java.util.List;
 public class SiteChannelsManagerTest {
     private SiteChannelsManager mSiteChannelsManager;
     @Rule
-    public NativeLibraryTestRule mNativeLibraryTestRule = new NativeLibraryTestRule();
+    public ChromeBrowserTestRule mChromeBrowserTestRule = new ChromeBrowserTestRule();
 
     @Before
     public void setUp() throws Exception {
-        mNativeLibraryTestRule.loadNativeLibraryAndInitBrowserProcess();
+        mChromeBrowserTestRule.loadNativeLibraryAndInitBrowserProcess();
 
         Context mContext = InstrumentationRegistry.getTargetContext();
         NotificationManagerProxy notificationManagerProxy = new NotificationManagerProxyImpl(