Extensions: Move id_util functions to crx_file component.

components/crx_file/id_util.h

Index: components/crx_file/id_util.h
diff --git a/extensions/common/id_util.h b/components/crx_file/id_util.h
similarity index 70%
rename from extensions/common/id_util.h
rename to components/crx_file/id_util.h
index 74e690dbf6012133b4261771da8cd2c4d87995c5..674fe6cb4f809a59122db051d743cae07cc9118b 100644
--- a/extensions/common/id_util.h
+++ b/components/crx_file/id_util.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef EXTENSIONS_COMMON_ID_UTIL_H_
-#define EXTENSIONS_COMMON_ID_UTIL_H_
+#ifndef COMPONENTS_CRX_FILE_ID_UTIL_H_
+#define COMPONENTS_CRX_FILE_ID_UTIL_H_
 
 #include <string>
 
@@ -11,7 +11,7 @@ namespace base {
 class FilePath;
 }
 
-namespace extensions {
+namespace crx_file {
 namespace id_util {
 
 // The number of bytes in a legal id.
@@ -29,7 +29,11 @@ std::string GenerateIdForPath(const base::FilePath& path);
 // sure the drive letter is uppercase.
 base::FilePath MaybeNormalizePath(const base::FilePath& path);
 
+// Checks if |id| is a valid extension-id. Extension-ids are used for anything
+// that comes in a CRX file, including apps, extensions, and components.
+bool IdIsValid(const std::string& id);
+
 }  // namespace id_util
-}  // namespace extensions
+}  // namespace crx_file
 
-#endif  // EXTENSIONS_COMMON_ID_UTIL_H_
+#endif  // COMPONENTS_CRX_FILE_ID_UTIL_H_