[Android] Fix settings screen crash

ProfileDataCache attempts to access ProfileData from ProfileDataSource
without first registering an observer. Detailed stack trace is linked to
the bug.

Bug: 1131499
Change-Id: Ifdfcedf1c4974a2cb3812ecaef93c4f490a01e71
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2426503
Commit-Queue: Tanmoy Mollik <triploblastic@chromium.org>
Commit-Queue: Alice Wang <aliceywang@chromium.org>
Reviewed-by: Alice Wang <aliceywang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809813}

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

@@ -197,8 +197,8 @@ public class ProfileDataCache implements ProfileDownloader.Observer, ProfileData
         ThreadUtils.assertOnUiThread();
         if (mObservers.isEmpty()) {
             if (mProfileDataSource != null) {
-                updateCacheFromProfileDataSource();
                 mProfileDataSource.addObserver(this);
+                updateCacheFromProfileDataSource();
             } else {
                 ProfileDownloader.addObserver(this);
             }