[Android Notifications] Use timestamp in notification channel IDs

- Implement GetWebsiteSettingLastModified for the
NotificationChannelsAndroidProvider by storing channel creation
timestamp within the channel IDs.

- This also has the beneficial side effect that each time a channel
is created in response to permission grant, it will have a unique ID,
so that channels deleted when site data is cleared will not be
restored the next time permission is granted/blocked.

- Note that NCAP.GetWebsiteSettingLastModified is currently only
called from tests, but in a future patch it will be pulled up to a
new provider interface and called by the HostContentSettingsMap
where it currently only calls the Pref Provider. 

Bug: 700377
Change-Id: I5363ae2baa7e0c92bb7768361d459cd024622b32
Reviewed-on: https://chromium-review.googlesource.com/567153
Commit-Queue: Anita Woodruff <awdf@chromium.org>
Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488198}

chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationPlatformBridge.java

@@ -393,8 +393,8 @@ public class NotificationPlatformBridge {
      *   2. NotificationConstants.EXTRA_NOTIFICATION_TAG - set by us on browser UI that should
      *     launch specific site settings, e.g. the web notifications Site Settings button.
      *
-     * See {@link SiteChannelsManager#toChannelId} and {@link SiteChannelsManager#toSiteOrigin} for
-     * how we convert origins to and from channel ids.
+     * See {@link SiteChannelsManager#createChannelId} and {@link SiteChannelsManager#toSiteOrigin}
+     * for how we convert origins to and from channel ids.
      *
      * See {@link #makePlatformTag} for details about the format of the EXTRA_NOTIFICATION tag.
      *
@@ -623,10 +623,12 @@ public class NotificationPlatformBridge {
         // Don't set a channelId for web apk notifications because the channel won't be
         // initialized for the web apk and it will crash on notify - see crbug.com/727178.
         // (It's okay to not set a channel on them because web apks don't target O yet.)
+        // TODO(crbug.com/700377): Channel ID should be retrieved from cache in native and passed
+        // through to here with other notification parameters.
         String channelId = forWebApk
                 ? null
                 : ChromeFeatureList.isEnabled(ChromeFeatureList.SITE_NOTIFICATION_CHANNELS)
-                        ? SiteChannelsManager.toChannelId(origin)
+                        ? SiteChannelsManager.getInstance().getChannelIdForOrigin(origin)
                         : ChannelDefinitions.CHANNEL_ID_SITES;
         if (useCustomLayouts(hasImage)) {
             return new CustomNotificationBuilder(context, channelId);

chrome/android/java/src/org/chromium/chrome/browser/notifications/NotificationSettingsBridge.java

@@ -4,8 +4,12 @@
 
 package org.chromium.chrome.browser.notifications;
 
+import android.app.NotificationManager;
+
 import org.chromium.base.BuildInfo;
 import org.chromium.base.annotations.CalledByNative;
+import org.chromium.chrome.browser.notifications.channels.Channel;
+import org.chromium.chrome.browser.notifications.channels.ChannelDefinitions;
 import org.chromium.chrome.browser.notifications.channels.SiteChannelsManager;
 
 /**
@@ -20,19 +24,23 @@ public class NotificationSettingsBridge {
     }
 
     /**
-     * Creates a notification channel for the given origin.
+     * Creates a notification channel for the given origin, unless a channel for this origin
+     * already exists.
+     *
      * @param origin The site origin to be used as the channel name.
+     * @param creationTime A string representing the time of channel creation.
      * @param enabled True if the channel should be initially enabled, false if
      *                it should start off as blocked.
+     * @return The channel created for this origin.
      */
     @CalledByNative
-    static void createChannel(String origin, boolean enabled) {
-        SiteChannelsManager.getInstance().createSiteChannel(origin, enabled);
+    static SiteChannel createChannel(String origin, long creationTime, boolean enabled) {
+        return SiteChannelsManager.getInstance().createSiteChannel(origin, creationTime, enabled);
     }
 
     @CalledByNative
-    static @NotificationChannelStatus int getChannelStatus(String origin) {
-        return SiteChannelsManager.getInstance().getChannelStatus(origin);
+    static @NotificationChannelStatus int getChannelStatus(String channelId) {
+        return SiteChannelsManager.getInstance().getChannelStatus(channelId);
     }
 
     @CalledByNative
@@ -41,22 +49,32 @@ public class NotificationSettingsBridge {
     }
 
     @CalledByNative
-    static void deleteChannel(String origin) {
-        SiteChannelsManager.getInstance().deleteSiteChannel(origin);
+    static void deleteChannel(String channelId) {
+        SiteChannelsManager.getInstance().deleteSiteChannel(channelId);
     }
 
     /**
      * Helper type for passing site channel objects across the JNI.
      */
     public static class SiteChannel {
+        private final String mId;
         private final String mOrigin;
+        private final long mTimestamp;
         private final @NotificationChannelStatus int mStatus;
 
-        public SiteChannel(String origin, @NotificationChannelStatus int status) {
+        public SiteChannel(String channelId, String origin, long creationTimestamp,
+                @NotificationChannelStatus int status) {
+            mId = channelId;
             mOrigin = origin;
+            mTimestamp = creationTimestamp;
             mStatus = status;
         }
 
+        @CalledByNative("SiteChannel")
+        public long getTimestamp() {
+            return mTimestamp;
+        }
+
         @CalledByNative("SiteChannel")
         public String getOrigin() {
             return mOrigin;
@@ -66,5 +84,18 @@ public class NotificationSettingsBridge {
         public @NotificationChannelStatus int getStatus() {
             return mStatus;
         }
+
+        @CalledByNative("SiteChannel")
+        public String getId() {
+            return mId;
+        }
+
+        public Channel toChannel() {
+            return new Channel(mId, mOrigin,
+                    mStatus == NotificationChannelStatus.BLOCKED
+                            ? NotificationManager.IMPORTANCE_NONE
+                            : NotificationManager.IMPORTANCE_DEFAULT,
+                    ChannelDefinitions.CHANNEL_GROUP_ID_SITES);
+        }
     }
 }

chrome/android/java/src/org/chromium/chrome/browser/notifications/channels/ChannelDefinitions.java

@@ -33,8 +33,8 @@ public class ChannelDefinitions {
     // TODO(crbug.com/700377): Deprecate the 'sites' channel.
     public static final String CHANNEL_ID_SITES = "sites";
     public static final String CHANNEL_ID_PREFIX_SITES = "web:";
+    public static final String CHANNEL_GROUP_ID_SITES = "sites";
     static final String CHANNEL_GROUP_ID_GENERAL = "general";
-    static final String CHANNEL_GROUP_ID_SITES = "sites";
     /**
      * Version number identifying the current set of channels. This must be incremented whenever
      * the set of channels returned by {@link #getStartupChannelIds()} or

chrome/android/java/src/org/chromium/chrome/browser/notifications/channels/ChannelsInitializer.java

@@ -52,10 +52,10 @@ public class ChannelsInitializer {
      */
     public void ensureInitialized(String channelId) {
         if (channelId.startsWith(ChannelDefinitions.CHANNEL_ID_PREFIX_SITES)) {
-            // TODO(crbug.com/700377): Initialize site channels via native, not directly as below,
-            // in order to keep track of when they were created.
-            SiteChannelsManager.getInstance().createSiteChannel(
-                    SiteChannelsManager.toSiteOrigin(channelId), /*enabled=*/true);
+            // If we have a valid site channel ID at this point, it is safe to assume a channel
+            // has already been created, since the only way to obtain a site channel ID is by
+            // creating a channel.
+            assert SiteChannelsManager.isValidSiteChannelId(channelId);
             return;
         }
         ChannelDefinitions.PredefinedChannel predefinedChannel =

chrome/android/java/src/org/chromium/chrome/browser/notifications/channels/SiteChannelsManager.java

@@ -6,6 +6,7 @@ package org.chromium.chrome.browser.notifications.channels;
 
 import android.app.NotificationManager;
 import android.content.Context;
+import android.support.annotation.Nullable;
 
 import org.chromium.base.ContextUtils;
 import org.chromium.base.VisibleForTesting;
@@ -22,6 +23,8 @@ import java.util.List;
  * Creates/deletes and queries our notification channels for websites.
  */
 public class SiteChannelsManager {
+    private static final String CHANNEL_ID_SEPARATOR = ";";
+
     private final NotificationManagerProxy mNotificationManager;
 
     public static SiteChannelsManager getInstance() {
@@ -41,34 +44,52 @@ public class SiteChannelsManager {
     }
 
     /**
-     * Creates a channel for the given origin. The channel will appear within the Sites channel
+     * Creates a channel for the given origin, unless a channel for this origin
+     * already exists. The channel will appear within the Sites channel
      * group, with default importance, or no importance if created as blocked.
      * @param origin The site origin, to be used as the channel's user-visible name.
+     * @param creationTime A string representing the time of channel creation.
      * @param enabled Determines whether the channel will be created as enabled or blocked.
+     * @return The channel created for the given origin.
      */
-    public void createSiteChannel(String origin, boolean enabled) {
+    public SiteChannel createSiteChannel(String origin, long creationTime, boolean enabled) {
+        SiteChannel preexistingChannel = getSiteChannelForOrigin(origin);
+        if (preexistingChannel != null) {
+            return preexistingChannel;
+        }
         // Channel group must be created before the channel.
         mNotificationManager.createNotificationChannelGroup(
                 ChannelDefinitions.getChannelGroup(ChannelDefinitions.CHANNEL_GROUP_ID_SITES));
-        mNotificationManager.createNotificationChannel(new Channel(toChannelId(origin), origin,
-                enabled ? NotificationManager.IMPORTANCE_DEFAULT
-                        : NotificationManager.IMPORTANCE_NONE,
-                ChannelDefinitions.CHANNEL_GROUP_ID_SITES));
+        SiteChannel siteChannel = new SiteChannel(createChannelId(origin, creationTime), origin,
+                creationTime,
+                enabled ? NotificationChannelStatus.ENABLED : NotificationChannelStatus.BLOCKED);
+        mNotificationManager.createNotificationChannel(siteChannel.toChannel());
+        return siteChannel;
+    }
+
+    private @Nullable SiteChannel getSiteChannelForOrigin(String origin) {
+        String normalizedOrigin = WebsiteAddress.create(origin).getOrigin();
+        for (SiteChannel channel : getSiteChannels()) {
+            if (channel.getOrigin().equals(normalizedOrigin)) {
+                return channel;
+            }
+        }
+        return null;
     }
 
     /**
-     * Deletes the channel associated with this origin.
+     * Deletes the channel associated with this channel ID.
      */
-    public void deleteSiteChannel(String origin) {
-        mNotificationManager.deleteNotificationChannel(toChannelId(origin));
+    public void deleteSiteChannel(String channelId) {
+        mNotificationManager.deleteNotificationChannel(channelId);
     }
 
     /**
-     * Gets the status of the channel associated with this origin.
+     * Gets the status of the channel associated with this channelId.
      * @return ALLOW, BLOCKED, or UNAVAILABLE (if the channel was never created or was deleted).
      */
-    public @NotificationChannelStatus int getChannelStatus(String origin) {
-        Channel channel = mNotificationManager.getNotificationChannel(toChannelId(origin));
+    public @NotificationChannelStatus int getChannelStatus(String channelId) {
+        Channel channel = mNotificationManager.getNotificationChannel(channelId);
         if (channel == null) return NotificationChannelStatus.UNAVAILABLE;
         return toChannelStatus(channel.getImportance());
     }
@@ -81,21 +102,34 @@ public class SiteChannelsManager {
         List<Channel> channels = mNotificationManager.getNotificationChannels();
         List<SiteChannel> siteChannels = new ArrayList<>();
         for (Channel channel : channels) {
-            if (channel.getGroupId() != null
-                    && channel.getGroupId().equals(ChannelDefinitions.CHANNEL_GROUP_ID_SITES)) {
-                siteChannels.add(new SiteChannel(
-                        toSiteOrigin(channel.getId()), toChannelStatus(channel.getImportance())));
+            if (isValidSiteChannelId(channel.getId())) {
+                siteChannels.add(toSiteChannel(channel));
             }
         }
         return siteChannels.toArray(new SiteChannel[siteChannels.size()]);
     }
 
+    private static SiteChannel toSiteChannel(Channel channel) {
+        String originAndTimestamp =
+                channel.getId().substring(ChannelDefinitions.CHANNEL_ID_PREFIX_SITES.length());
+        String[] parts = originAndTimestamp.split(CHANNEL_ID_SEPARATOR);
+        assert parts.length == 2;
+        return new SiteChannel(channel.getId(), parts[0], Long.parseLong(parts[1]),
+                toChannelStatus(channel.getImportance()));
+    }
+
+    static boolean isValidSiteChannelId(String channelId) {
+        return channelId.startsWith(ChannelDefinitions.CHANNEL_ID_PREFIX_SITES)
+                && channelId.substring(ChannelDefinitions.CHANNEL_ID_PREFIX_SITES.length())
+                           .contains(CHANNEL_ID_SEPARATOR);
+    }
+
     /**
-     * Converts a site's origin to a canonical channel id for that origin.
+     * Converts a site's origin and creation timestamp to a canonical channel id.
      */
-    public static String toChannelId(String origin) {
+    public static String createChannelId(String origin, long creationTime) {
         return ChannelDefinitions.CHANNEL_ID_PREFIX_SITES
-                + WebsiteAddress.create(origin).getOrigin();
+                + WebsiteAddress.create(origin).getOrigin() + CHANNEL_ID_SEPARATOR + creationTime;
     }
 
     /**
@@ -105,7 +139,8 @@ public class SiteChannelsManager {
      */
     public static String toSiteOrigin(String channelId) {
         assert channelId.startsWith(ChannelDefinitions.CHANNEL_ID_PREFIX_SITES);
-        return channelId.substring(ChannelDefinitions.CHANNEL_ID_PREFIX_SITES.length());
+        return channelId.substring(ChannelDefinitions.CHANNEL_ID_PREFIX_SITES.length())
+                .split(CHANNEL_ID_SEPARATOR)[0];
     }
 
     /**
@@ -119,4 +154,10 @@ public class SiteChannelsManager {
                 return NotificationChannelStatus.ENABLED;
         }
     }
+
+    public String getChannelIdForOrigin(String origin) {
+        SiteChannel channel = getSiteChannelForOrigin(origin);
+        // Fall back to generic Sites channel if a channel for this origin doesn't exist.
+        return channel == null ? ChannelDefinitions.CHANNEL_ID_SITES : channel.getId();
+    }
 }

chrome/android/java/src/org/chromium/chrome/browser/preferences/website/SingleWebsitePreferences.java

@@ -385,14 +385,13 @@ public class SingleWebsitePreferences extends PreferenceFragment
                 public boolean onPreferenceClick(Preference preference) {
                     // There is no guarantee that a channel has been initialized yet for sites
                     // that were granted permission before the channel-initialization-on-grant
-                    // code was in place. So initialize it here before launching the settings.
-                    // TODO(awdf): Once upgrade code is in place, quickly check this ran instead.
-                    // (Right now this is laggy!)
-                    SiteChannelsManager.getInstance().createSiteChannel(
-                            mSite.getAddress().getOrigin(), value == ContentSetting.ALLOW);
-
-                    launchOsChannelSettings(preference.getContext(),
-                            SiteChannelsManager.toChannelId(mSite.getAddress().getOrigin()));
+                    // code was in place. However, getChannelIdForOrigin will fall back to the
+                    // generic Sites channel if no specific channel has been created for the given
+                    // origin, so it is safe to open the channel settings for whatever channel ID
+                    // it returns.
+                    String channelId = SiteChannelsManager.getInstance().getChannelIdForOrigin(
+                            mSite.getAddress().getOrigin());
+                    launchOsChannelSettings(preference.getContext(), channelId);
                     return true;
                 }
             });

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

@@ -230,12 +230,14 @@ public class ChannelsInitializerTest {
     public void testEnsureInitialized_singleOriginSiteChannel() throws Exception {
         if (!BuildInfo.isAtLeastO()) return;
         String origin = "https://example.com";
-        mChannelsInitializer.ensureInitialized(SiteChannelsManager.toChannelId(origin));
+        long creationTime = 621046800000L;
+        mChannelsInitializer.ensureInitialized(
+                SiteChannelsManager.createChannelId(origin, creationTime));
 
         assertThat(getChannelsIgnoringMiscellaneous(), hasSize(1));
 
         Channel channel = getChannelsIgnoringMiscellaneous().get(0);
-        assertThat(channel.getId(), is(SiteChannelsManager.toChannelId(origin)));
+        assertThat(channel.getId(), is(SiteChannelsManager.createChannelId(origin, creationTime)));
         assertThat(channel.getName().toString(), is("https://example.com"));
         assertThat(channel.getImportance(), is(NotificationManager.IMPORTANCE_DEFAULT));
         assertThat(channel.getGroupId(), is(ChannelDefinitions.CHANNEL_GROUP_ID_SITES));

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

@@ -67,18 +67,19 @@ public class SiteChannelsManagerTest {
     @MinAndroidSdkLevel(26)
     @SmallTest
     public void testCreateSiteChannel_enabled() throws Exception {
-        mSiteChannelsManager.createSiteChannel("https://chromium.org", true);
+        mSiteChannelsManager.createSiteChannel("https://chromium.org", 62102180000L, true);
         assertThat(Arrays.asList(mSiteChannelsManager.getSiteChannels()), hasSize(1));
         NotificationSettingsBridge.SiteChannel channel = mSiteChannelsManager.getSiteChannels()[0];
         assertThat(channel.getOrigin(), is("https://chromium.org"));
         assertThat(channel.getStatus(), matchesChannelStatus(NotificationChannelStatus.ENABLED));
+        assertThat(channel.getTimestamp(), is(62102180000L));
     }
 
     @Test
     @MinAndroidSdkLevel(26)
     @SmallTest
     public void testCreateSiteChannel_disabled() throws Exception {
-        mSiteChannelsManager.createSiteChannel("https://example.com", false);
+        mSiteChannelsManager.createSiteChannel("https://example.com", 0L, false);
         assertThat(Arrays.asList(mSiteChannelsManager.getSiteChannels()), hasSize(1));
         NotificationSettingsBridge.SiteChannel channel = mSiteChannelsManager.getSiteChannels()[0];
         assertThat(channel.getOrigin(), is("https://example.com"));
@@ -89,8 +90,9 @@ public class SiteChannelsManagerTest {
     @MinAndroidSdkLevel(26)
     @SmallTest
     public void testDeleteSiteChannel_channelExists() throws Exception {
-        mSiteChannelsManager.createSiteChannel("https://chromium.org", true);
-        mSiteChannelsManager.deleteSiteChannel("https://chromium.org");
+        NotificationSettingsBridge.SiteChannel channel =
+                mSiteChannelsManager.createSiteChannel("https://chromium.org", 0L, true);
+        mSiteChannelsManager.deleteSiteChannel(channel.getId());
         assertThat(Arrays.asList(mSiteChannelsManager.getSiteChannels()), hasSize(0));
     }
 
@@ -98,7 +100,7 @@ public class SiteChannelsManagerTest {
     @MinAndroidSdkLevel(26)
     @SmallTest
     public void testDeleteSiteChannel_channelDoesNotExist() throws Exception {
-        mSiteChannelsManager.createSiteChannel("https://chromium.org", true);
+        mSiteChannelsManager.createSiteChannel("https://chromium.org", 0L, true);
         mSiteChannelsManager.deleteSiteChannel("https://some-other-origin.org");
         assertThat(Arrays.asList(mSiteChannelsManager.getSiteChannels()), hasSize(1));
     }
@@ -107,8 +109,9 @@ public class SiteChannelsManagerTest {
     @MinAndroidSdkLevel(26)
     @SmallTest
     public void testGetChannelStatus_channelCreatedAsEnabled() throws Exception {
-        mSiteChannelsManager.createSiteChannel("https://chromium.org", true);
-        assertThat(mSiteChannelsManager.getChannelStatus("https://chromium.org"),
+        NotificationSettingsBridge.SiteChannel channel =
+                mSiteChannelsManager.createSiteChannel("https://chromium.org", 0L, true);
+        assertThat(mSiteChannelsManager.getChannelStatus(channel.getId()),
                 matchesChannelStatus(NotificationChannelStatus.ENABLED));
     }
 
@@ -118,11 +121,9 @@ public class SiteChannelsManagerTest {
     public void testGetChannelStatus_channelCreatedAsBlocked() throws Exception {
         assertThat(mSiteChannelsManager.getChannelStatus("https://foobar.com"),
                 matchesChannelStatus(NotificationChannelStatus.UNAVAILABLE));
-        mSiteChannelsManager.createSiteChannel("https://foobar.com", false);
-        assertThat(mNotificationManagerProxy.getNotificationChannel("web:https://foobar.com")
-                           .getImportance(),
-                is(NotificationManager.IMPORTANCE_NONE));
-        assertThat(mSiteChannelsManager.getChannelStatus("https://foobar.com"),
+        NotificationSettingsBridge.SiteChannel channel =
+                mSiteChannelsManager.createSiteChannel("https://foobar.com", 0L, false);
+        assertThat(mSiteChannelsManager.getChannelStatus(channel.getId()),
                 matchesChannelStatus(NotificationChannelStatus.BLOCKED));
     }
 
@@ -130,7 +131,7 @@ public class SiteChannelsManagerTest {
     @MinAndroidSdkLevel(26)
     @SmallTest
     public void testGetChannelStatus_channelNotCreated() throws Exception {
-        assertThat(mSiteChannelsManager.getChannelStatus("https://chromium.org"),
+        assertThat(mSiteChannelsManager.getChannelStatus("invalid-channel-id"),
                 matchesChannelStatus(NotificationChannelStatus.UNAVAILABLE));
     }
 
@@ -138,9 +139,10 @@ public class SiteChannelsManagerTest {
     @MinAndroidSdkLevel(26)
     @SmallTest
     public void testGetChannelStatus_channelCreatedThenDeleted() throws Exception {
-        mSiteChannelsManager.createSiteChannel("https://chromium.org", true);
-        mSiteChannelsManager.deleteSiteChannel("https://chromium.org");
-        assertThat(mSiteChannelsManager.getChannelStatus("https://chromium.org"),
+        NotificationSettingsBridge.SiteChannel channel =
+                mSiteChannelsManager.createSiteChannel("https://chromium.org", 0L, true);
+        mSiteChannelsManager.deleteSiteChannel(channel.getId());
+        assertThat(mSiteChannelsManager.getChannelStatus(channel.getId()),
                 matchesChannelStatus(NotificationChannelStatus.UNAVAILABLE));
     }
 

chrome/android/junit/src/org/chromium/chrome/browser/notifications/NotificationPlatformBridgeUnitTest.java

@@ -120,7 +120,7 @@ public class NotificationPlatformBridgeUnitTest {
         // Returns the expected origin for a channel id associated with a particular origin.
         assertEquals("https://example.com",
                 NotificationPlatformBridge.getOriginFromChannelId(
-                        SiteChannelsManager.toChannelId("https://example.com")));
+                        SiteChannelsManager.createChannelId("https://example.com", 62104680000L)));
 
         // Returns null for a channel id that is not associated with a particular origin.
         assertNull(NotificationPlatformBridge.getOriginFromChannelId(

chrome/browser/notifications/notification_channels_provider_android.h

@@ -5,12 +5,14 @@
 #ifndef CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_CHANNELS_PROVIDER_ANDROID_H_
 #define CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_CHANNELS_PROVIDER_ANDROID_H_
 
+#include <map>
 #include <string>
 #include <tuple>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/time/clock.h"
 #include "components/content_settings/core/browser/content_settings_observable_provider.h"
 #include "components/content_settings/core/browser/content_settings_observer.h"
 #include "components/content_settings/core/browser/content_settings_rule.h"
@@ -23,15 +25,17 @@
 enum NotificationChannelStatus { ENABLED, BLOCKED, UNAVAILABLE };
 
 struct NotificationChannel {
-  NotificationChannel(std::string origin, NotificationChannelStatus status)
-      : origin(origin), status(status) {}
+  NotificationChannel(const std::string& id,
+                      const std::string& origin,
+                      const base::Time& timestamp,
+                      NotificationChannelStatus status);
+  NotificationChannel(const NotificationChannel& other);
   bool operator==(const NotificationChannel& other) const {
     return origin == other.origin && status == other.status;
   }
-  bool operator<(const NotificationChannel& other) const {
-    return std::tie(origin, status) < std::tie(other.origin, other.status);
-  }
-  std::string origin;
+  const std::string id;
+  const std::string origin;
+  const base::Time timestamp;
   NotificationChannelStatus status = NotificationChannelStatus::UNAVAILABLE;
 };
 
@@ -47,7 +51,9 @@ class NotificationChannelsProviderAndroid
    public:
     virtual ~NotificationChannelsBridge() = default;
     virtual bool ShouldUseChannelSettings() = 0;
-    virtual void CreateChannel(const std::string& origin, bool enabled) = 0;
+    virtual NotificationChannel CreateChannel(const std::string& origin,
+                                              const base::Time& timestamp,
+                                              bool enabled) = 0;
     virtual NotificationChannelStatus GetChannelStatus(
         const std::string& origin) = 0;
     virtual void DeleteChannel(const std::string& origin) = 0;
@@ -71,22 +77,48 @@ class NotificationChannelsProviderAndroid
   void ClearAllContentSettingsRules(ContentSettingsType content_type) override;
   void ShutdownOnUIThread() override;
 
+  base::Time GetWebsiteSettingLastModified(
+      const ContentSettingsPattern& primary_pattern,
+      const ContentSettingsPattern& secondary_pattern,
+      ContentSettingsType content_type,
+      const content_settings::ResourceIdentifier& resource_identifier);
+
  private:
   explicit NotificationChannelsProviderAndroid(
-      std::unique_ptr<NotificationChannelsBridge> bridge);
+      std::unique_ptr<NotificationChannelsBridge> bridge,
+      std::unique_ptr<base::Clock> clock);
   friend class NotificationChannelsProviderAndroidTest;
 
+  std::vector<NotificationChannel> UpdateCachedChannels() const;
+
   void CreateChannelIfRequired(const std::string& origin_string,
                                NotificationChannelStatus new_channel_status);
 
+  void InitCachedChannels();
+
   std::unique_ptr<NotificationChannelsBridge> bridge_;
+
   bool should_use_channels_;
 
-  // This cache is updated every time GetRuleIterator is called. It is used to
-  // check if any channels have changed their status since the previous call,
-  // in order to notify observers. This is necessary to detect channels getting
-  // blocked/enabled by the user, in the absence of a callback for this event.
-  std::vector<NotificationChannel> cached_channels_;
+  std::unique_ptr<base::Clock> clock_;
+
+  // Flag to keep track of whether |cached_channels_| has been initialized yet.
+  bool initialized_cached_channels_;
+
+  // Map of origin - NotificationChannel. Channel status may be out of date.
+  // This cache is completely refreshed every time GetRuleIterator is called;
+  // entries are also added and deleted when channels are added and deleted.
+  // This cache serves three purposes:
+  //
+  // 1. For looking up the channel ID for an origin.
+  //
+  // 2. For looking up the channel creation timestamp for an origin.
+  //
+  // 3. To check if any channels have changed status since the last time
+  //    they were checked, in order to notify observers. This is necessary to
+  //    detect channels getting blocked/enabled by the user, in the absence of a
+  //    callback for this event.
+  std::map<std::string, NotificationChannel> cached_channels_;
 
   base::WeakPtrFactory<NotificationChannelsProviderAndroid> weak_factory_;