Add a way to send the resource percentage signal to the RC.

components/offline_pages/core/background/resource_tracker_observer_stub.h

Index: components/offline_pages/core/background/resource_tracker_observer_stub.h
diff --git a/components/offline_pages/core/background/resource_tracker_observer_stub.h b/components/offline_pages/core/background/resource_tracker_observer_stub.h
new file mode 100644
index 0000000000000000000000000000000000000000..270b9064dad051919dd8918f80c0ace5518b7826
--- /dev/null
+++ b/components/offline_pages/core/background/resource_tracker_observer_stub.h
@@ -0,0 +1,37 @@
+// 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_BACKGROUND_RESOURCE_TRACKER_OBSERVER_STUB_H_
+#define COMPONENTS_OFFLINE_PAGES_CORE_BACKGROUND_RESOURCE_TRACKER_OBSERVER_STUB_H_
+
+#include "components/offline_pages/core/background/resource_data_type.h"
+#include "components/offline_pages/core/background/resource_tracker_observer.h"
+
+namespace offline_pages {
+
+class ResourceTrackerObserverStub : public ResourceTrackerObserver {
+ public:
+  ResourceTrackerObserverStub();
+
+  ~ResourceTrackerObserverStub();
+
+  // When we are notified of a resource load starting or ending, pass the
+  // information along to the offliner.
+  void ObserveResourceTracking(const ResourceDataType type,
+                               int64_t started_count,
+                               int64_t completed_count) override;
+
+  // Returns the most recently seen counts for a specific resource type.
+  void GetResourcePercentageCounts(const ResourceDataType type,
+                                   int64_t* started,
+                                   int64_t* completed);
+
+ private:
+  int64_t images_started_;
+  int64_t images_completed_;
+};
+
+}  // namespace offline_pages
+
+#endif  // COMPONENTS_OFFLINE_PAGES_CORE_BACKGROUND_RESOURCE_TRACKER_OBSERVER_STUBH_