[Android backup] Restore nothing if signed in user isn't valid

chrome/android/java/src/org/chromium/chrome/browser/ChromeBackupAgent.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ChromeBackupAgent.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ChromeBackupAgent.java b/chrome/android/java/src/org/chromium/chrome/browser/ChromeBackupAgent.java
index a95ec53a1afed2847628a8c94db8a3b1f2afe8bb..1e537559a24eac78bb09c9d33a03af738ffe82a3 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ChromeBackupAgent.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ChromeBackupAgent.java
@@ -4,6 +4,8 @@
 
 package org.chromium.chrome.browser;
 
+import android.accounts.Account;
+import android.accounts.AccountManager;
 import android.annotation.TargetApi;
 import android.app.backup.BackupAgent;
 import android.app.backup.BackupDataInput;
@@ -60,26 +62,51 @@ public class ChromeBackupAgent extends BackupAgent {
         // Android Backup
     }
 
+    // May be overriden by downstream products that access account information in a different way.
+    protected Account[] getAccounts() {
+        Log.d(TAG, "Getting accounts from AccountManager");
+        AccountManager manager = (AccountManager) getSystemService(ACCOUNT_SERVICE);
+        return manager.getAccounts();
+    }
+
+    private boolean accountExistsOnDevice(String userName) {

[Bernhard Bauer, 2016/05/23 12:41:24]

I would also mention that we're not using AccountManagerHelper here because we
don't have a custom application class to set it up.

[aberent, 2016/06/01 12:34:31]

Done. I have also put a comment at the top of the class explaining that nothing
in it can depend on ChromeApplication.

+        for (Account account: getAccounts()) {
+            if (account.name.equals(userName)) return true;
+        }
+        return false;
+    }
+
     @Override
     public void onRestoreFinished() {
-        SharedPreferences sharedPrefs =
-                PreferenceManager.getDefaultSharedPreferences(ChromeBackupAgent.this);
+        if (getApplicationContext() instanceof ChromeApplication) {
+            // This should never happen in real use, but will happen during testing if Chrome is
+            // already running (even in background, started to provide a service, for example).
+            Log.w(TAG, "Running with wrong type of Application class");
+            return;
+        }
+        SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this);
         Set<String> prefNames = sharedPrefs.getAll().keySet();
         // Save the user name for later restoration.
         String userName = sharedPrefs.getString(ChromeSigninController.SIGNED_IN_ACCOUNT_KEY, null);
+        Log.d(TAG, "Previous signed in user name = " + userName);
+        // If the user hasn't signed in, or can't sign in, then don't restore anything.
+        if (userName == null || !accountExistsOnDevice(userName)) {
+            boolean commitResult = sharedPrefs.edit().clear().commit();
+            Log.d(TAG, "onRestoreFinished complete, nothing restored; commit result = "

[Bernhard Bauer, 2016/05/23 12:40:15]

Use a format string for logging. (Or just remove these log statements
completely.)

[aberent, 2016/06/01 12:34:31]

Done.

+                    + commitResult);
+            return;
+        }
+
         SharedPreferences.Editor editor = sharedPrefs.edit();
         // Throw away prefs we don't want to restore.
         Set<String> restoredPrefs = new HashSet<>(Arrays.asList(RESTORED_ANDROID_PREFS));
         for (String pref : prefNames) {
-            Log.d(TAG, "Checking pref " + pref);
             if (!restoredPrefs.contains(pref)) editor.remove(pref);
         }
         // Because FirstRunSignInProcessor.FIRST_RUN_FLOW_SIGNIN_COMPLETE is not restored Chrome
         // will sign in the user on first run to the account in FIRST_RUN_FLOW_SIGNIN_ACCOUNT_NAME
         // if any. If the rest of FRE has been completed this will happen silently.
-        if (userName != null) {
-            editor.putString(FirstRunSignInProcessor.FIRST_RUN_FLOW_SIGNIN_ACCOUNT_NAME, userName);
-        }
+        editor.putString(FirstRunSignInProcessor.FIRST_RUN_FLOW_SIGNIN_ACCOUNT_NAME, userName);
         boolean commitResult = editor.commit();
 
         Log.d(TAG, "onRestoreFinished complete; commit result = " + commitResult);