Add app indexing reporter public class.

chrome/android/java/src/org/chromium/chrome/browser/historyreport/AppIndexingReporter.java

Index: chrome/android/java/src/org/chromium/chrome/browser/historyreport/AppIndexingReporter.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/historyreport/AppIndexingReporter.java b/chrome/android/java/src/org/chromium/chrome/browser/historyreport/AppIndexingReporter.java
new file mode 100644
index 0000000000000000000000000000000000000000..d6add855b6e604772fbea6e51b0c28a3e756a800
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/historyreport/AppIndexingReporter.java
@@ -0,0 +1,31 @@
+// Copyright 2017 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.historyreport;
+
+import org.chromium.base.ContextUtils;
+import org.chromium.chrome.browser.ChromeApplication;
+
+/** Base class for reporting entities to App Indexing. */
+public class AppIndexingReporter {
+    private static final String TAG = "AppIndexingReporter";
+    private static AppIndexingReporter sInstance;
+
+    public static AppIndexingReporter getInstance() {
+        if (sInstance == null) {
+            sInstance = ((ChromeApplication) ContextUtils.getApplicationContext())
+                                .createAppIndexingReporter();
+        }
+        return sInstance;
+    }
+
+    /**
+     * Reports provided entity to on-device index.
+     * Base class does not implement any reporting, and call is a no-op. Child classes should
+     * implement this functionality.
+     */
+    public void reportEntityJsonLd(String url, String json) {
+        // Overriden by private class. Base class does nothing.
+    }
+}