Created the dialog offering the user to merge their account data or keep it

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 5d2bcd99193dba66e781bf2cc24ab0c85430129a..03fbbe1e6170c2eb5665b55b7dada418a0fca33b 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
@@ -218,6 +218,17 @@ public class SigninManager implements AccountTrackerService.OnSystemAccountsSeed
         sSignInAccessPoint = accessPoint;
     }
 
+    /**
+     * Checks whether a different account was previously signed in and so the confirm data sync
+     * dialog should be shown.
+     * @param newAccountName The name of the proposed account.
+     * @return Whether the previous account was different to the proposed account.
+     */
+    public static boolean shouldShowDataSyncDialog(String newAccountName) {

[newt (away), 2016/02/25 18:01:32]

Now that this the SigninInvestigator logic has been otherwise removed from
SigninManager, you could just inline this code in AccountFirstRunView.

[PEConn, 2016/02/25 20:45:12]

Done.

+        return SigninInvestigator.investigate(newAccountName)
+                == InvestigatedScenario.DIFFERENT_ACCOUNT;
+    }
+
     private void logSigninCompleteAccessPoint() {
         RecordHistogram.recordEnumeratedHistogram(
                 "Signin.SigninCompletedAccessPoint", sSignInAccessPoint, SigninAccessPoint.MAX);
@@ -292,7 +303,7 @@ public class SigninManager implements AccountTrackerService.OnSystemAccountsSeed
     public void onSystemAccountsSeedingComplete() {
         if (mSignInState != null && mSignInState.blockedOnAccountSeeding) {
             mSignInState.blockedOnAccountSeeding = false;
-            progressSignInFlowInvestigateScenario();
+            progressSignInFlowCheckPolicy();
         }
     }
 
@@ -366,7 +377,7 @@ public class SigninManager implements AccountTrackerService.OnSystemAccountsSeed
 
     private void progressSignInFlowSeedSystemAccounts() {
         if (AccountTrackerService.get(mContext).checkAndSeedSystemAccounts()) {
-            progressSignInFlowInvestigateScenario();
+            progressSignInFlowCheckPolicy();
         } else if (AccountIdProvider.getInstance().canBeUsed(mContext)) {
             mSignInState.blockedOnAccountSeeding = true;
         } else {
@@ -381,11 +392,11 @@ public class SigninManager implements AccountTrackerService.OnSystemAccountsSeed
     }
 
     /**
-     * If sign-in is interactive and the user is changing accounts, display a confirmation dialog.
+     * Continues the signin flow by checking if there is a policy that the account is subject to.
      */
-    private void progressSignInFlowInvestigateScenario() {
-        if (!mSignInState.isInteractive()) {
-            progressSignInFlowCheckPolicy();
+    private void progressSignInFlowCheckPolicy() {
+        if (mSignInState == null) {
+            Log.w(TAG, "Ignoring sign in progress request as no pending sign in.");
             return;
         }
 
@@ -394,41 +405,6 @@ public class SigninManager implements AccountTrackerService.OnSystemAccountsSeed
             return;
         }
 
-        // TODO(skym): Warn for high risk upgrade scenario, crbug.com/572754.
-        if (SigninInvestigator.investigate(mSignInState.account.name)
-                == InvestigatedScenario.DIFFERENT_ACCOUNT) {
-            mSignInState.displayedDialog =
-                    ConfirmAccountChangeFragment.newInstance(mSignInState.account.name);
-            mSignInState.displayedDialog.show(
-                    mSignInState.activity.getFragmentManager(), CONFIRM_ACCOUNT_CHANGED_DIALOG_TAG);
-        } else {
-            // Do not display dialog, just sign-in.
-            progressSignInFlowCheckPolicy();
-        }
-    }
-
-    /**
-     * Called from ConfirmAccountChangeFragment if the new account name was confirmed.
-     */
-    void progressInteractiveSignInFlowAccountConfirmed() {
-        if (mSignInState == null || mSignInState.displayedDialog == null) {
-            // Stop if sign-in was cancelled or this is a duplicate click event.
-            return;
-        }
-        mSignInState.displayedDialog = null;
-
-        progressSignInFlowCheckPolicy();
-    }
-
-    /**
-     * Continues the signin flow by checking if there is a policy that the account is subject to.
-     */
-    private void progressSignInFlowCheckPolicy() {
-        if (mSignInState == null) {
-            Log.w(TAG, "Ignoring sign in progress request as no pending sign in.");
-            return;
-        }
-
         if (!nativeShouldLoadPolicyForUser(mSignInState.account.name)) {
             // Proceed with the sign-in flow without checking for policy if it can be determined
             // that this account can't have management enabled based on the username.
@@ -465,6 +441,7 @@ public class SigninManager implements AccountTrackerService.OnSystemAccountsSeed
             return;
         }
 
+        // TODO(peconn): Move this and other UI interactions into AccountSigninView.
         Log.d(TAG, "Account has policy management");
         mSignInState.displayedDialog = ConfirmManagedSigninFragment.newInstance(managementDomain);
         mSignInState.displayedDialog.show(