[Android] Fix component build again.

base/android/memory_pressure_listener_android.h

 // 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.
 
 #ifndef BASE_ANDROID_MEMORY_PRESSURE_LISTENER_ANDROID_H_
 #define BASE_ANDROID_MEMORY_PRESSURE_LISTENER_ANDROID_H_
 
 #include "base/android/jni_android.h"
 
 namespace base {
 namespace android {
 
 // Implements the C++ counter part of MemoryPressureListener.java
-class MemoryPressureListenerAndroid {
+class BASE_EXPORT MemoryPressureListenerAndroid {
  public:
   static bool Register(JNIEnv* env);
 
   static void RegisterSystemCallback(JNIEnv* env);
 
   // Called by JNI.
   static void OnMemoryPressure(int memory_pressure_type);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MemoryPressureListenerAndroid);
 };
 
 }  // namespace android
 }  // namespace base
 
 #endif  // BASE_ANDROID_MEMORY_PRESSURE_LISTENER_ANDROID_H_