Added UMA metrics for ChromeOS first-run UI.

chrome/browser/chromeos/first_run/metrics.h

+// Copyright 2013 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_CHROMEOS_FIRST_RUN_METRICS_H_
+#define CHROME_BROWSER_CHROMEOS_FIRST_RUN_METRICS_H_
+
+namespace chromeos {
+namespace first_run {
+
+enum TutorialCompletion {
+  // User left tutorial before finish.
+  kTutorialNotFinished,

[Alexei Svitkine (slow), 2014/01/15 16:02:38]

I believe enums should use FOO_BAR style in Chromium style.

[dzhioev (left Google), 2014/01/15 22:12:54]

Both styles are allowed, furthermore Google Style Guide says that "Preferably,
the individual enumerators should be named like constants." (
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml?showone=Enumer...
).
Also kFooBar style is widely used in Chromium sources.

[Alexei Svitkine (slow), 2014/01/15 22:21:36]

Chromiums style overrides the Google one in this case: "Though the Google C++
Style Guide now says to use kConstantNaming for enums, Chromium was written
using MACRO_STYLE naming.  Continue to use this style for consistency."

However, if you say that ChromeOS already uses kStyle - then I won't press it
here (since the argument is "for consistency").

+  // Tutorial was completed with "Got It" button.
+  kTutorialCompletedWithGotIt,
+  // Tutorial was completed with "Keep Exploring" button, i.e. Help App was
+  // launched after tutorial.
+  kTutorialCompletedWithKeepExploring,
+  // Must be the last element.
+  kTutorialCompletionSize
+};
+
+}  // namespace first_run
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_FIRST_RUN_METRICS_H_