predictors: Make the resource_prefetch_predictor accessible from Java.

chrome/browser/predictors/resource_prefetch_predictor_android.cc

+// Copyright 2016 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 "chrome/browser/predictors/resource_prefetch_predictor_android.h"
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_string.h"
+#include "chrome/browser/predictors/resource_prefetch_predictor.h"
+#include "chrome/browser/predictors/resource_prefetch_predictor_factory.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_android.h"
+#include "jni/ResourcePrefetchPredictor_jni.h"
+
+using base::android::JavaParamRef;
+using base::android::ScopedJavaLocalRef;
+
+namespace predictors {
+
+namespace {
+ResourcePrefetchPredictor* ResourcePrefetchPredictorFromProfileAndroid(
+    const JavaParamRef<jobject>& j_profile) {
+  Profile* profile = ProfileAndroid::FromProfileAndroid(j_profile);
+  if (!profile)
+    return nullptr;
+  return ResourcePrefetchPredictorFactory::GetInstance()->GetForProfile(
+      profile);
+}
+
+}  // namespace
+
+static jboolean StartPrefetching(JNIEnv* env,
+                                 const JavaParamRef<jclass>& clazz,
+                                 const JavaParamRef<jobject>& j_profile,
+                                 const JavaParamRef<jstring>& j_url) {
+  auto predictor = ResourcePrefetchPredictorFromProfileAndroid(j_profile);
+  if (!predictor)
+    return false;
+  GURL url = GURL(base::android::ConvertJavaStringToUTF16(env, j_url));
+  predictor->StartPrefetching(url);
+
+  return true;
+}
+
+static jboolean StopPrefetching(JNIEnv* env,
+                                const JavaParamRef<jclass>& clazz,
+                                const JavaParamRef<jobject>& j_profile,
+                                const JavaParamRef<jstring>& j_url) {
+  auto predictor = ResourcePrefetchPredictorFromProfileAndroid(j_profile);
+  if (!predictor)
+    return false;
+  GURL url = GURL(base::android::ConvertJavaStringToUTF16(env, j_url));
+  predictor->StopPrefetching(url);
+
+  return true;
+}
+
+bool RegisterResourcePrefetchPredictor(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace predictors