Fix a crash in SigninManager.finishSignIn()

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..fd556aacb9fb9c7c7e89272176919c2421baebc8 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
@@ -395,6 +395,11 @@ public class SigninManager {
     }
 
     private void finishSignIn(AccountIdsAndNames accountIdsAndNames) {
+        if (mSignInAccount == null) {
+            Log.w(TAG, "Sign in request was canceled; aborting finishSignIn().");
+            return;
+        }
+
         // Cache the signed-in account name.
         ChromeSigninController.get(mContext).setSignedInAccountName(mSignInAccount.name);