[sync] Sign user out of Chrome on dashboard stop and reset

chrome/android/java/src/org/chromium/chrome/browser/signin/SigninManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/signin/SigninManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/signin/SigninManager.java b/chrome/android/java/src/org/chromium/chrome/browser/signin/SigninManager.java
index 995a0e5e7850767ae1a8428deac2087b5caa54db..410abadf275aa39c4f1240350a99f38e0a3c3235 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/signin/SigninManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/signin/SigninManager.java
@@ -587,6 +587,19 @@ public class SigninManager implements AccountTrackerService.OnSystemAccountsSeed
         onSignOutDone();
     }
 
+    // Sign out can be initiated in native code, outside this SigninManager.
+    // onNativeSignOut() notifies us of this so we can clean up android specific
+    // state.
+    @CalledByNative
+    private void onNativeSignOut() {
+        // If mSignOutCallback != null, two things are true:
+        // 1) signOut() is in progress, so we don't need to invoke it again.
+        // 2) If we did invoke it again, doing so would not be idempotent.
+        if (ChromeSigninController.get(mContext).isSignedIn() && mSignOutCallback == null) {
+            signOut();
+        }
+    }
+
     private void onSignOutDone() {
         if (mSignOutCallback != null) {
             new Handler().post(mSignOutCallback);