Prefer SyncService over ProfileSyncService in foreign_session_helper

SyncService is the interface, ProfileSyncService is the concrete
implementation. Generally no clients should need to use the conrete
implementation - for one, testing will be much easier once everyone
uses the interface only.

Bug: 924508
Change-Id: Ia210665f8f02512053d1a60d627dea0f22758387
Reviewed-on: https://chromium-review.googlesource.com/c/1461119
Auto-Submit: Marc Treib <treib@chromium.org>
Commit-Queue: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#630662}
static jlong JNI_ForeignSessionHelper_Init(
    JNIEnv* env,
    const JavaParamRef<jobject>& profile) {
  ForeignSessionHelper* foreign_session_helper = new ForeignSessionHelper(
      ProfileAndroid::FromProfileAndroid(profile));
  return reinterpret_cast<intptr_t>(foreign_session_helper);
}

static jlong JNI_ForeignSessionHelper_Init(
    JNIEnv* env,
    const JavaParamRef<jobject>& profile) {
  ForeignSessionHelper* foreign_session_helper = new ForeignSessionHelper(
      ProfileAndroid::FromProfileAndroid(profile));
  return reinterpret_cast<intptr_t>(foreign_session_helper);
}
