[Android] Fix sign-in crash fix.

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 1e74bb82def6f5764ca6efb4e9f6da6e6e99b796..6f13d9571c8a464311b11f53fcdf7d0edf8a7f1d 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
@@ -280,9 +280,10 @@ public class SigninManager {
      */
     public void startSignIn(Activity activity, final Account account, boolean passive,
             final SignInFlowObserver observer) {
-        assert mSignInActivity == null;
-        assert mSignInAccount == null;
-        assert mSignInFlowObserver == null;
+        if (mSignInAccount != null) {
+            Log.w(TAG, "Ignoring sign-in request as another sign-in request is pending.");
+            return;
+        }
 
         if (mFirstRunCheckIsPending) {
             Log.w(TAG, "Ignoring sign-in request until the First Run check completes.");