Introduce a stable set of errors for inline install

chrome/common/extensions/webstore_install_result.h

Index: chrome/common/extensions/webstore_install_result.h
diff --git a/chrome/browser/extensions/webstore_install_result.h b/chrome/common/extensions/webstore_install_result.h
similarity index 71%
rename from chrome/browser/extensions/webstore_install_result.h
rename to chrome/common/extensions/webstore_install_result.h
index 91f91f2a63c06c90277293e2de52fef97e292710..38d04f1785349fa0aad5c3a1d70362d3e7f59fd4 100644
--- a/chrome/browser/extensions/webstore_install_result.h
+++ b/chrome/common/extensions/webstore_install_result.h
@@ -2,14 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_BROWSER_EXTENSIONS_WEBSTORE_INSTALL_RESULT_H_
-#define CHROME_BROWSER_EXTENSIONS_WEBSTORE_INSTALL_RESULT_H_
+#ifndef CHROME_COMMON_EXTENSIONS_WEBSTORE_INSTALL_RESULT_H_
+#define CHROME_COMMON_EXTENSIONS_WEBSTORE_INSTALL_RESULT_H_
 
 namespace extensions {
 
 namespace webstore_install {
 
 // Result codes returned by WebstoreStandaloneInstaller and its subclasses.
+// IMPORTANT: Keep this list in sync with both the definition in
+// chrome/common/extensions/api/webstore.json and
+// chrome/common/extensions/api/webstore/webstore_install_constants.cc!
 enum Result {
   // Successful operation.
   SUCCESS,
@@ -59,11 +62,15 @@ enum Result {
   LAUNCH_FEATURE_DISABLED,
 
   // The launch feature is not supported for the extension type.
-  LAUNCH_UNSUPPORTED_EXTENSION_TYPE
+  LAUNCH_UNSUPPORTED_EXTENSION_TYPE,
+
+  // The final (and unused) result type for enum verification.
+  // New results should go above this entry, and this entry should be updated.
+  RESULT_LAST = LAUNCH_UNSUPPORTED_EXTENSION_TYPE,
 };
 
 }  // namespace webstore_install
 
 }  // namespace extensions
 
-#endif  // CHROME_BROWSER_EXTENSIONS_WEBSTORE_INSTALL_RESULT_H_
+#endif  // CHROME_COMMON_EXTENSIONS_WEBSTORE_INSTALL_RESULT_H_