WebView: Add channel info for UMA

components/version_info/version_string.h

Index: components/version_info/version_string.h
diff --git a/components/version_info/version_string.h b/components/version_info/version_string.h
new file mode 100644
index 0000000000000000000000000000000000000000..083cfbf33cbac31b9238165267878da850bb4bb7
--- /dev/null
+++ b/components/version_info/version_string.h
@@ -0,0 +1,20 @@
+// 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_VERSION_INFO_VERSION_STRING_H_
+#define COMPONENTS_VERSION_INFO_VERSION_STRING_H_
+
+#include <string>
+
+namespace version_info {
+
+// Returns a version string to be displayed in "About Chromium" dialog.
+// |modifier| is a string representation of the channel with system specific
+// information, e.g. "dev SyzyASan". It is appended to the returned version
+// information if non-empty.
+std::string GetVersionStringWithModifier(const std::string& modifier);
+
+}  // namespace version_info
+
+#endif  // COMPONENTS_VERSION_INFO_VERSION_STRING_H_