Add the JNI code in order to let Java use the InterestsFetcher.

chrome/browser/interests/android/interests_service.h

Index: chrome/browser/interests/android/interests_service.h
diff --git a/chrome/browser/interests/android/interests_service.h b/chrome/browser/interests/android/interests_service.h
new file mode 100644
index 0000000000000000000000000000000000000000..8a197786e57c527dde7bc15d48756681f22a5a0d
--- /dev/null
+++ b/chrome/browser/interests/android/interests_service.h
@@ -0,0 +1,50 @@
+// Copyright 2015 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 CHROME_BROWSER_INTERESTS_ANDROID_INTERESTS_SERVICE_H_
+#define CHROME_BROWSER_INTERESTS_ANDROID_INTERESTS_SERVICE_H_
+
+#include <jni.h>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "chrome/browser/interests/interests_fetcher.h"
+
+class Profile;

[Bernhard Bauer, 2015/10/08 09:04:41]

Empty line afterwards.

[PEConn, 2015/10/08 09:40:55]

Done.

+namespace base {
+namespace android {
+template<typename T> class ScopedJavaGlobalRef;

[Marc Treib, 2015/10/08 08:26:51]

Ugh. TBH, I'd prefer to just include the header here. (But of course this is
okay too, especially since Bernhard suggested forward declaring)

[PEConn, 2015/10/08 09:40:55]

Done.

+}
+}
+
+// Provides a list of user interests to Java
+class InterestsService {
+ public:
+  explicit InterestsService(Profile* profile);
+  virtual ~InterestsService();
+
+  void Destroy(JNIEnv* env, jobject obj);
+  static bool Register(JNIEnv* env);
+  void GetInterests(JNIEnv* env,
+                    jobject obj,
+                    jobject j_callback);
+
+ private:
+  void OnObtainedInterests(
+      scoped_ptr<InterestsFetcher> fetcher,
+      const base::android::ScopedJavaGlobalRef<jobject>& j_callback,
+      scoped_ptr<std::vector<InterestsFetcher::Interest>> interests);
+
+  static jobjectArray ConvertInterestsToJava(

[Bernhard Bauer, 2015/10/08 09:04:41]

Can you add a comment that explains why this is a static private method (instead
of being in an anonymous namespace)?

[PEConn, 2015/10/08 09:40:55]

Moved to anonymous namespace.

+      JNIEnv* env,
+      scoped_ptr<std::vector<InterestsFetcher::Interest>> interests);
+
+  Profile* profile_;
+
+  base::WeakPtrFactory<InterestsService> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterestsService);
+};
+
+#endif  // CHROME_BROWSER_INTERESTS_ANDROID_INTERESTS_SERVICE_H_