Clear webapp storage when site data is cleared

chrome/browser/android/webapps/webapp_registry.h

+// 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_ANDROID_WEBAPPS_WEBAPP_REGISTRY_H_
+#define CHROME_BROWSER_ANDROID_WEBAPPS_WEBAPP_REGISTRY_H_
+
+#include "base/android/jni_android.h"
+#include "base/callback_forward.h"
+
+// WebappRegistry is the C++ counterpart of
+// org.chromium.chrome.browser.webapp's WebappRegistry in Java.
+class WebappRegistry {
+ public:
+  // Registers JNI hooks.
+  static bool RegisterWebappRegistry(JNIEnv* env);
+
+  // Cleans up data stored by webapps. Must be called from the DB thread.
+  static void CleanupWebappsOnIOThread(const base::Closure& callback);
+
+ private:
+  WebappRegistry() = delete;
+  ~WebappRegistry() = delete;
+
+  DISALLOW_COPY_AND_ASSIGN(WebappRegistry);
+};
+
+#endif  // CHROME_BROWSER_ANDROID_WEBAPPS_WEBAPP_REGISTRY_H_