Refactor ActivityStatus to not store current activity

ui/base/android/window_android.cc

 // Copyright 2013 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 "ui/base/android/window_android.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_helper.h"
 #include "base/android/scoped_java_ref.h"
 #include "jni/WindowAndroid_jni.h"
 #include "ui/base/android/window_android_observer.h"
 
 namespace ui {
 
 using base::android::AttachCurrentThread;
 using base::android::ScopedJavaLocalRef;
 
 WindowAndroid::WindowAndroid(JNIEnv* env, jobject obj)
   : weak_java_window_(env, obj) {
 }
 
 void WindowAndroid::Destroy(JNIEnv* env, jobject obj) {
   delete this;
 }
 
-ScopedJavaLocalRef<jobject> WindowAndroid::GetJavaObject() {
+ScopedJavaLocalRef<jobject> WindowAndroid::GetJavaObject() const {
   return weak_java_window_.get(AttachCurrentThread());
 }
 
 bool WindowAndroid::RegisterWindowAndroid(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 WindowAndroid::~WindowAndroid() {
 }
 
@@ skipping 44 matching lines @@
 // ----------------------------------------------------------------------------
 // Native JNI methods
 // ----------------------------------------------------------------------------
 
 jlong Init(JNIEnv* env, jobject obj) {
   WindowAndroid* window = new WindowAndroid(env, obj);
   return reinterpret_cast<intptr_t>(window);
 }
 
 }  // namespace ui