First step towards component build for Android.

base/android/jni_helper.h

Index: base/android/jni_helper.h
diff --git a/base/android/jni_helper.h b/base/android/jni_helper.h
index 22883cbbcfcab5d4d1f6a559a6e38968cbd43d21..895bf95a9d12786838a173ff55884477f1b8a469 100644
--- a/base/android/jni_helper.h
+++ b/base/android/jni_helper.h
@@ -7,13 +7,14 @@
 
 #include <jni.h>
 
+#include "base/base_export.h"
 #include "base/android/scoped_java_ref.h"
 
 // Manages WeakGlobalRef lifecycle.
 // This class is not thread-safe w.r.t. get() and reset(). Multiple threads may
 // safely use get() concurrently, but if the user calls reset() (or of course,
 // calls the destructor) they'll need to provide their own synchronization.
-class JavaObjectWeakGlobalRef {
+class BASE_EXPORT JavaObjectWeakGlobalRef {
  public:
   JavaObjectWeakGlobalRef();
   JavaObjectWeakGlobalRef(const JavaObjectWeakGlobalRef& orig);
@@ -34,7 +35,7 @@ class JavaObjectWeakGlobalRef {
 
 // Get the real object stored in the weak reference returned as a
 // ScopedJavaLocalRef.
-base::android::ScopedJavaLocalRef<jobject> GetRealObject(
+BASE_EXPORT base::android::ScopedJavaLocalRef<jobject> GetRealObject(
     JNIEnv* env, jweak obj);
 
 #endif  // BASE_ANDROID_JNI_HELPER_H_