[SignIn] Fix AccountSigninView for asynchronous updateAccounts()

updateAccounts() now takes a callback to allow code to run once the
accounts have actually been fetched.

This also adds some check in updateAccounts() to ensure it only updates
the accounts when expected (i.e. when the user isn't signed in).

BUG=678543,672255

Review-Url: https://codereview.chromium.org/2616643005
Cr-Commit-Position: refs/heads/master@{#442932}

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

@@ -226,13 +226,31 @@ public class AccountSigninView extends FrameLayout implements ProfileDownloader.
     }
 
     /**
-     * Refresh the list of available system accounts.
+     * Refresh the list of available system accounts asynchronously. This is a convenience method
+     * that will ignore whether the accounts updating was actually successful.
      */
     private void updateAccounts() {
-        if (mSignedIn || mProfileData == null) return;
+        updateAccounts(new Callback<Boolean>() {
+            @Override
+            public void onResult(Boolean result) {}
+        });
+    }
+
+    /**
+     * Refresh the list of available system accounts asynchronously.
+     *
+     * @param callback Called once the accounts have been refreshed. Boolean indicates whether the
+     *                 accounts haven been successfully updated.
+     */
+    private void updateAccounts(final Callback<Boolean> callback) {
+        if (mSignedIn || mProfileData == null) {
+            callback.onResult(false);
+            return;
+        }
 
         if (!checkGooglePlayServicesAvailable()) {
             setUpSigninButton(false);
+            callback.onResult(false);
             return;
         }
 
@@ -256,6 +274,13 @@ public class AccountSigninView extends FrameLayout implements ProfileDownloader.
                     updatingGmsDialog.dismiss();
                 }
                 mIsGooglePlayServicesOutOfDate = false;
+
+                if (mSignedIn) {
+                    // If sign-in completed in the mean time, return in order to avoid showing the
+                    // wrong state in the UI.
+                    return;
+                }
+
                 mAccountNames = result;
 
                 int accountToSelect = 0;
@@ -263,6 +288,7 @@ public class AccountSigninView extends FrameLayout implements ProfileDownloader.
                     accountToSelect = mAccountNames.indexOf(mForcedAccountName);
                     if (accountToSelect < 0) {
                         mListener.onFailedToSetForcedAccount(mForcedAccountName);
+                        callback.onResult(false);
                         return;
                     }
                 } else {
@@ -275,6 +301,7 @@ public class AccountSigninView extends FrameLayout implements ProfileDownloader.
                 mSigninChooseView.updateAccounts(mAccountNames, accountToSelect, mProfileData);
                 if (mAccountNames.isEmpty()) {
                     setUpSigninButton(false);
+                    callback.onResult(true);
                     return;
                 }
                 setUpSigninButton(true);
@@ -283,7 +310,10 @@ public class AccountSigninView extends FrameLayout implements ProfileDownloader.
 
                 // Determine how the accounts have changed. Each list should only have unique
                 // elements.
-                if (oldAccountNames == null || oldAccountNames.isEmpty()) return;
+                if (oldAccountNames == null || oldAccountNames.isEmpty()) {
+                    callback.onResult(true);
+                    return;
+                }
 
                 if (!mAccountNames.get(accountToSelect).equals(
                         oldAccountNames.get(oldSelectedAccount))) {
@@ -299,7 +329,7 @@ public class AccountSigninView extends FrameLayout implements ProfileDownloader.
                         showConfirmSigninPageAccountTrackerServiceCheck();
                     }
                 }
-
+                callback.onResult(true);
             }
         });
     }
@@ -568,11 +598,16 @@ public class AccountSigninView extends FrameLayout implements ProfileDownloader.
      */
     public void switchToForcedAccountMode(String forcedAccountName) {
         mForcedAccountName = forcedAccountName;
-        updateAccounts();
+        updateAccounts(new Callback<Boolean>() {
+            @Override
+            public void onResult(Boolean result) {
+                if (!result) return;
                 assert TextUtils.equals(getSelectedAccountName(), mForcedAccountName);
                 switchToSignedMode();
                 assert TextUtils.equals(getSelectedAccountName(), mForcedAccountName);
             }
+        });
+    }
 
     /**
      * @return Whether the view is in signed in mode.