Implement server-suggested update check backoff

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
index cc68e6613d0150ec72614748a25ad2855164633c..bc4d7e1d098bb8925aa9818868a4e12ecce9a993 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
@@ -51,16 +51,28 @@ public class WebappDataStorage {
             "last_check_web_manifest_update_time";
 
     // The last time that the WebAPK update request completed (successfully or unsuccessfully).
-    static final String KEY_LAST_WEBAPK_UPDATE_REQUEST_COMPLETE_TIME =
-            "last_webapk_update_request_complete_time";
+    static final String KEY_LAST_UPDATE_REQUEST_COMPLETE_TIME = "last_update_request_complete_time";
 
     // Whether the last WebAPK update request succeeded.
-    static final String KEY_DID_LAST_WEBAPK_UPDATE_REQUEST_SUCCEED =
-            "did_last_webapk_update_request_succeed";
+    static final String KEY_DID_LAST_UPDATE_REQUEST_SUCCEED = "did_last_update_request_succeed";
 
     // The number of times that updating a WebAPK in the background has been requested.
     static final String KEY_UPDATE_REQUESTED = "update_requested";
 
+    // Whether to check updates less frequently.
+    static final String KEY_RELAX_UPDATES = "relax_updates";
+
+    // Number of milliseconds between checks for whether the WebAPK's Web Manifest has changed.
+    public static final long UPDATE_INTERVAL = TimeUnit.DAYS.toMillis(3L);
+
+    // Number of milliseconds between checks of updates for a WebAPK that is expected to check
+    // updates less frequently. crbug.com/680128.
+    public static final long RELAXED_UPDATE_INTERVAL = TimeUnit.DAYS.toMillis(30L);
+
+    // Number of milliseconds to wait before re-requesting an updated WebAPK from the WebAPK
+    // server if the previous update attempt failed.
+    public static final long RETRY_UPDATE_DURATION = TimeUnit.HOURS.toMillis(12L);
+
     // Unset/invalid constants for last used times and URLs. 0 is used as the null last used time as
     // WebappRegistry assumes that this is always a valid timestamp.
     static final long LAST_USED_UNSET = 0;
@@ -302,9 +314,10 @@ public class WebappDataStorage {
         editor.remove(KEY_URL);
         editor.remove(KEY_SCOPE);
         editor.remove(KEY_LAST_CHECK_WEB_MANIFEST_UPDATE_TIME);
-        editor.remove(KEY_LAST_WEBAPK_UPDATE_REQUEST_COMPLETE_TIME);
-        editor.remove(KEY_DID_LAST_WEBAPK_UPDATE_REQUEST_SUCCEED);
+        editor.remove(KEY_LAST_UPDATE_REQUEST_COMPLETE_TIME);
+        editor.remove(KEY_DID_LAST_UPDATE_REQUEST_SUCCEED);
         editor.remove(KEY_UPDATE_REQUESTED);
+        editor.remove(KEY_RELAX_UPDATES);
         editor.apply();
     }
 
@@ -367,7 +380,7 @@ public class WebappDataStorage {
      * Returns the completion time of the last check for whether the WebAPK's Web Manifest was
      * updated. This time needs to be set when the WebAPK is registered.
      */
-    long getLastCheckForWebManifestUpdateTime() {
+    private long getLastCheckForWebManifestUpdateTime() {
         return mPreferences.getLong(KEY_LAST_CHECK_WEB_MANIFEST_UPDATE_TIME, LAST_USED_INVALID);
     }
 
@@ -376,7 +389,7 @@ public class WebappDataStorage {
      */
     void updateTimeOfLastWebApkUpdateRequestCompletion() {
         mPreferences.edit()
-                .putLong(KEY_LAST_WEBAPK_UPDATE_REQUEST_COMPLETE_TIME, sClock.currentTimeMillis())
+                .putLong(KEY_LAST_UPDATE_REQUEST_COMPLETE_TIME, sClock.currentTimeMillis())
                 .apply();
     }
 
@@ -385,24 +398,21 @@ public class WebappDataStorage {
      * This time needs to be set when the WebAPK is registered.
      */
     long getLastWebApkUpdateRequestCompletionTime() {

[Xi Han, 2017/03/08 14:40:50]

This function is called by WebApkUpdateManagerTest, so we can't make it private.

[pkotwicz, 2017/03/08 16:29:10]

Fair enough

-        return mPreferences.getLong(
-                KEY_LAST_WEBAPK_UPDATE_REQUEST_COMPLETE_TIME, LAST_USED_INVALID);
+        return mPreferences.getLong(KEY_LAST_UPDATE_REQUEST_COMPLETE_TIME, LAST_USED_INVALID);
     }
 
     /**
-     * Updates the result of whether the last update request to WebAPK Server succeeded.
+     * Updates whether the last update request to WebAPK Server succeeded.
      */
     void updateDidLastWebApkUpdateRequestSucceed(boolean success) {
-        mPreferences.edit()
-                .putBoolean(KEY_DID_LAST_WEBAPK_UPDATE_REQUEST_SUCCEED, success)
-                .apply();
+        mPreferences.edit().putBoolean(KEY_DID_LAST_UPDATE_REQUEST_SUCCEED, success).apply();
     }
 
     /**
      * Returns whether the last update request to WebAPK Server succeeded.
      */
     boolean getDidLastWebApkUpdateRequestSucceed() {
-        return mPreferences.getBoolean(KEY_DID_LAST_WEBAPK_UPDATE_REQUEST_SUCCEED, false);
+        return mPreferences.getBoolean(KEY_DID_LAST_UPDATE_REQUEST_SUCCEED, false);
     }
 
     /**
@@ -426,6 +436,42 @@ public class WebappDataStorage {
         return mPreferences.getInt(KEY_UPDATE_REQUESTED, 0);
     }
 
+    /**
+     * Returns whether the previous WebAPK update attempt succeeded. Returns true if there has not
+     * been any update attempts.
+     */
+    boolean didPreviousUpdateSucceed() {
+        long lastUpdateCompletionTime = getLastWebApkUpdateRequestCompletionTime();
+        if (lastUpdateCompletionTime == WebappDataStorage.LAST_USED_INVALID
+                || lastUpdateCompletionTime == WebappDataStorage.LAST_USED_UNSET) {
+            return true;
+        }
+        return getDidLastWebApkUpdateRequestSucceed();
+    }
+
+    /** Sets whether we should check for updates less frequently. */
+    void setRelaxedUpdates(boolean relaxUpdates) {
+        mPreferences.edit().putBoolean(KEY_RELAX_UPDATES, relaxUpdates).apply();
+    }
+
+    /** Returns whether we should check for updates less frequently. */
+    private boolean shouldRelaxUpdates() {
+        return mPreferences.getBoolean(KEY_RELAX_UPDATES, false);
+    }
+
+    /** Returns whether we should check for update. */
+    boolean shouldCheckForUpdate() {
+        long checkUpdatesInterval =
+                shouldRelaxUpdates() ? RELAXED_UPDATE_INTERVAL : UPDATE_INTERVAL;
+        long now = sClock.currentTimeMillis();
+        long sinceLastCheckDurationMs = now - getLastCheckForWebManifestUpdateTime();
+        if (sinceLastCheckDurationMs >= checkUpdatesInterval) return true;
+
+        long sinceLastUpdateRequestDurationMs = now - getLastWebApkUpdateRequestCompletionTime();
+        return sinceLastUpdateRequestDurationMs >= WebappDataStorage.RETRY_UPDATE_DURATION
+                && !didPreviousUpdateSucceed();
+    }
+
     protected WebappDataStorage(String webappId) {
         mId = webappId;
         mPreferences = ContextUtils.getApplicationContext().getSharedPreferences(