Include tab IDs when reporting data use accounting.

components/data_usage/core/data_use_annotator.h

Index: components/data_usage/core/data_use_annotator.h
diff --git a/components/data_usage/core/data_use_annotator.h b/components/data_usage/core/data_use_annotator.h
new file mode 100644
index 0000000000000000000000000000000000000000..ea7932de044c58e771af20388e6fe8f8a9f6f485
--- /dev/null
+++ b/components/data_usage/core/data_use_annotator.h
@@ -0,0 +1,37 @@
+// 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 COMPONENTS_DATA_USAGE_CORE_DATA_USE_ANNOTATOR_H_
+#define COMPONENTS_DATA_USAGE_CORE_DATA_USE_ANNOTATOR_H_
+
+#include "base/callback_forward.h"

[bengr, 2015/11/05 00:00:38]

Why do you need callback_forward.h and not callback.h?

[sclittle, 2015/11/05 01:22:48]

We do need it now, because of the new typedef here. We didn't need it before
because we were just using a const ref of the callback type, and callback.h is
pretty big. From
https://code.google.com/p/chromium/codesearch#chromium/src/base/callback.h&l=12:

"NOTE: Header files that do not require the full definition of Callback or
Closure should #include "base/callback_forward.h" instead of this file."

+#include "base/memory/scoped_ptr.h"
+
+namespace net {
+class URLRequest;
+}
+
+namespace data_usage {
+
+struct DataUse;
+
+// Interface for an object that can annotate DataUse objects with additional
+// information.
+class DataUseAnnotator {
+ public:
+  virtual ~DataUseAnnotator() {}
+
+  // Annotate |data_use| with additional information, possibly from |request|,
+  // before passing the annotated |data_use| to |callback|. |request| is passed
+  // in as a non-const pointer so that the DataUseAnnotator can add UserData on
+  // to the |request| if desired.
+  virtual void Annotate(
+      net::URLRequest* request,
+      scoped_ptr<DataUse> data_use,
+      const base::Callback<void(scoped_ptr<DataUse>)>& callback) = 0;
+};
+
+}  // namespace data_usage
+
+#endif  // COMPONENTS_DATA_USAGE_CORE_DATA_USE_ANNOTATOR_H_