predictors: Make the resource_prefetch_predictor accessible from Java.

chrome/android/java/src/org/chromium/chrome/browser/customtabs/ResourcePrefetchPredictor.java

Index: chrome/android/java/src/org/chromium/chrome/browser/customtabs/ResourcePrefetchPredictor.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/ResourcePrefetchPredictor.java b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/ResourcePrefetchPredictor.java
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+++ b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/ResourcePrefetchPredictor.java
@@ -0,0 +1,52 @@
+// 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.
+
+package org.chromium.chrome.browser.customtabs;
+
+import org.chromium.base.ThreadUtils;
+import org.chromium.base.annotations.JNINamespace;
+import org.chromium.chrome.browser.profiles.Profile;
+
+/**
+ * Interface to the resource prefetch predictor.
+ *
+ * This allows to initiate and abort prefetches of likely subresources, based on
+ * the local browsing history.
+ */
+@JNINamespace("predictors")
+class ResourcePrefetchPredictor {
+    private final Profile mProfile;
+
+    /**
+     * @param profile The profile used to get the prefetch predictor.
+     */
+    public ResourcePrefetchPredictor(Profile profile) {
+        mProfile = profile;
+    }
+
+    /**
+     * Starts a prefetch for a URL.
+     *
+     * @param url The URL to start the prefetch for.
+     * @return false in case the ResourcePrefetchPredictor is not usable.
+     */
+    public boolean startPrefetching(String url) {
+        ThreadUtils.assertOnUiThread();
+        return nativeStartPrefetching(mProfile, url);
+    }
+
+    /**
+     * Stops a prefetch for a URL, if one is in progress.
+     *
+     * @param url The URL to stop the prefetch of.
+     * @return false in case the ResourcePrefetchPredictor is not usable.
+     */
+    public boolean stopPrefetching(String url) {
+        ThreadUtils.assertOnUiThread();
+        return nativeStopPrefetching(mProfile, url);
+    }
+
+    private static native boolean nativeStartPrefetching(Profile profile, String url);
+    private static native boolean nativeStopPrefetching(Profile profile, String url);
+}