Re-enable child account detection, now behind a flag.

chrome/android/java/src/org/chromium/chrome/browser/child_accounts/ChildAccountService.java

Index: chrome/android/java/src/org/chromium/chrome/browser/child_accounts/ChildAccountService.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/child_accounts/ChildAccountService.java b/chrome/android/java/src/org/chromium/chrome/browser/child_accounts/ChildAccountService.java
index 012513b662f534b09c9194ea6404e281264c2ff9..1b6136a09a450acc9dee2dd8acab24ee45df1651 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/child_accounts/ChildAccountService.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/child_accounts/ChildAccountService.java
@@ -111,9 +111,10 @@ public class ChildAccountService {
         }
         Account account = googleAccounts[0];
 
-        if (shouldForceChildAccount(account)) {
-            mHasChildAccount = true;
-            callback.onChildAccountChecked(true);
+        Boolean forceChildAccount = shouldForceChildAccount(account);
+        if (forceChildAccount != null) {
+            mHasChildAccount = forceChildAccount;
+            callback.onChildAccountChecked(mHasChildAccount);
             return;
         }
 
@@ -151,10 +152,12 @@ public class ChildAccountService {
             }}, CHILD_ACCOUNT_TIMEOUT_MS);
     }
 
-    private boolean shouldForceChildAccount(Account account) {
+    private Boolean shouldForceChildAccount(Account account) {
         String childAccountName = CommandLine.getInstance().getSwitchValue(
                 ChromeSwitches.CHILD_ACCOUNT);
-        return childAccountName != null && account.name.equals(childAccountName);
+        if (childAccountName != null && account.name.equals(childAccountName)) return true;
+        if (!isChildAccountDetectionEnabled()) return false;
+        return null;
     }
 
     private boolean getFutureResult() {
@@ -213,9 +216,14 @@ public class ChildAccountService {
         }
     }
 
+    private boolean isChildAccountDetectionEnabled() {
+        return nativeIsChildAccountDetectionEnabled();
+    }
+
     public void onChildAccountSigninComplete() {
         nativeOnChildAccountSigninComplete();
     }
 
+    private native boolean nativeIsChildAccountDetectionEnabled();
     private native void nativeOnChildAccountSigninComplete();
 }