Run the later parts of startup as UI thread tasks

content/browser/android/android_startup_observer.cc

+// TODO: Insert description here. (generated by aberent)
+
+#include "android_startup_observer.h"
+
+#include "jni/StartupObserver_jni.h"
+
+namespace content {
+
+AndroidStartupObserver::AndroidStartupObserver(jobject java_observer)
+    : java_observer_(java_observer) {}
+
+void AndroidStartupObserver::AllTasksRun() {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  Java_StartupObserver_allTasksRun(env, java_observer_);
+}
+
+bool AndroidStartupObserver::RegisterStartupObserver(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+AndroidStartupObserver::~AndroidStartupObserver() {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  env->DeleteGlobalRef(java_observer_);
+}
+
+}  // namespace content