[Autofill] Add protobuf for Google Wallet risk parameters and a utility function for filling it out.

chrome/browser/autofill/risk/machine_fingerprint.h

Index: chrome/browser/autofill/risk/machine_fingerprint.h
diff --git a/chrome/browser/autofill/risk/machine_fingerprint.h b/chrome/browser/autofill/risk/machine_fingerprint.h
new file mode 100644
index 0000000000000000000000000000000000000000..8416dab1f233c50f95b42cb1203261125d433f82
--- /dev/null
+++ b/chrome/browser/autofill/risk/machine_fingerprint.h
@@ -0,0 +1,32 @@
+// Copyright (c) 2012 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_AUTOFILL_RISK_MACHINE_FINGERPRINT_H_
+#define CHROME_BROWSER_AUTOFILL_RISK_MACHINE_FINGERPRINT_H_
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace gfx {
+class Rect;
+}
+
+namespace autofill {
+namespace risk {

[Albert Bodenhamer, 2012/12/18 17:42:22]

Is it worth doing a nested namespace here?

[Ilya Sherman, 2012/12/19 01:50:08]

I think this is tidier than including "Risk" in the function name.  Since
Autofill code should already be in the autofill namespace (note: not all of it
currently is, but it *should* be), invocations of the method will look like
"risk::GetMachineFingerprint(...)", which IMO is clear and easier to read than
"GetMachineFingerprintForRisk(...)" or something like that.

[Albert Bodenhamer, 2012/12/19 22:10:17]

Ok.

+
+class BrowserNativeFingerprinting;
+
+// Fills |data| with statistics that, collectively, constitute a unique
+// fingerprint for this (machine, |gaia_id|) pair.  The GAIA id is the user id
+// for Google's authentication system.

[Albert Bodenhamer, 2012/12/19 22:10:17]

Since this is specific to Risk, it's probably worth mentioning in a comment that
this data is intended for use in fraud reduction.

[Ilya Sherman, 2012/12/20 04:06:49]

Done.

+void GetMachineFingerprint(int64 gaia_id,
+                           const gfx::Rect& window_rect,
+                           const gfx::Rect& content_rect,
+                           scoped_ptr<BrowserNativeFingerprinting> data);
+
+}  // namespace risk
+}  // namespace autofill
+
+
+#endif  // CHROME_BROWSER_AUTOFILL_RISK_MACHINE_FINGERPRINT_H_