[Offline Pages] Add a GCMAppHandler for offline page prefetch.

components/offline_pages/core/prefetch/prefetch_gcm_handler.h

Index: components/offline_pages/core/prefetch/prefetch_gcm_handler.h
diff --git a/components/offline_pages/core/prefetch/prefetch_gcm_handler.h b/components/offline_pages/core/prefetch/prefetch_gcm_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..c522eb872deefac2d04d531fcfe7102647a01f96
--- /dev/null
+++ b/components/offline_pages/core/prefetch/prefetch_gcm_handler.h
@@ -0,0 +1,25 @@
+// 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.
+
+#ifndef COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_GCM_HANDLER_H_
+#define COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_GCM_HANDLER_H_
+
+namespace offline_pages {
+
+class PrefetchGCMHandler;
+
+// Main class and entry point for the Offline Pages Prefetching feature, that
+// controls the lifetime of all major subcomponents of the prefetching system.
+class PrefetchGCMHandler {
+ public:
+  PrefetchGCMHandler() = default;
+  virtual ~PrefetchGCMHandler() = default;
+
+  // TODO(dewittj): Add methods for acquiring an Instance ID token to this
+  // interface.
+};
+
+}  // namespace offline_pages
+
+#endif  // COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_GCM_HANDLER_H_