[Autofill] Add support for signin promo on Android

chrome/browser/android/signin/signin_promo_util_android.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/android/signin/signin_promo_util_android.h"
+
+#include "base/android/context_utils.h"
+#include "base/android/jni_android.h"
+#include "jni/SigninPromoUtil_jni.h"
+#include "ui/android/window_android.h"
+
+namespace chrome {
+namespace android {
+
+// static
+void SigninPromoUtilAndroid::StartAccountSigninActivityForPromo(
+    content::ContentViewCore* content_view_core,
+    signin_metrics::AccessPoint access_point) {
+  if (content_view_core) {
+    Java_SigninPromoUtil_openAccountSigninActivityForPromo(
+        base::android::AttachCurrentThread(),
+        content_view_core->GetWindowAndroid()->GetJavaObject().obj(),

[Ted C, 2016/07/19 20:09:19]

While reparenting, the window android can be null.  But since this is show via a
user action, it "shouldn't" be possible.  If we are unsure, I think it would be
also fine to null check the window android ref as well.

[Mathieu, 2016/07/19 21:00:19]

Done.

+        jint(access_point));
+  }
+}
+
+// static
+bool SigninPromoUtilAndroid::Register(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace android
+}  // namespace chrome