Fix AccountManagerHelper assert access from FRE.

FRE was made to lazily load the libraries, but it attempts
to access the AccountManagerHelper before it has been
fully initialized.  To avoid this, use ChromeBrowserInitializer
to the pre native initialization early, which will call into:
ProcessInitializationHandler#handlePreNativeInitialization, which
does AccountManagerHelper.initializeAccountManagerHelper.

BUG=

Review-Url: https://codereview.chromium.org/2610173002
Cr-Commit-Position: refs/heads/master@{#441419}

chrome/android/java/src/org/chromium/chrome/browser/firstrun/FirstRunActivity.java

@@ -24,6 +24,7 @@ import org.chromium.chrome.browser.customtabs.CustomTabActivity;
 import org.chromium.chrome.browser.customtabs.CustomTabsConnection;
 import org.chromium.chrome.browser.document.ChromeLauncherActivity;
 import org.chromium.chrome.browser.init.ChromeBrowserInitializer;
+import org.chromium.chrome.browser.init.EmptyBrowserParts;
 import org.chromium.chrome.browser.metrics.UmaUtils;
 import org.chromium.chrome.browser.net.spdyproxy.DataReductionProxySettings;
 import org.chromium.chrome.browser.preferences.datareduction.DataReductionPromoUtils;
@@ -173,6 +174,8 @@ public class FirstRunActivity extends AppCompatActivity implements FirstRunPageD
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
+        ChromeBrowserInitializer.getInstance(this).handlePreNativeStartup(new EmptyBrowserParts());
+
         if (savedInstanceState != null) {
             mFreProperties = savedInstanceState;
         } else if (getIntent() != null) {
@@ -513,7 +516,8 @@ public class FirstRunActivity extends AppCompatActivity implements FirstRunPageD
     private void ensureBrowserProcessInitialized() {
         if (mNativeSideIsInitialized) return;
         try {
-            ChromeBrowserInitializer.getInstance(this).handleSynchronousStartup();
+            ChromeBrowserInitializer.getInstance(this).handlePostNativeStartup(
+                    false, new EmptyBrowserParts());
             mNativeSideIsInitialized = true;
         } catch (ProcessInitException e) {
             Log.e(TAG, "Unable to load native library.", e);