Implement chrome.systemPrivate.getIncognitoModeAvailability extension API function

chrome/browser/extensions/extension_preference_api.cc

Index: chrome/browser/extensions/extension_preference_api.cc
diff --git a/chrome/browser/extensions/extension_preference_api.cc b/chrome/browser/extensions/extension_preference_api.cc
index 871d99bcac5fca3cc678cfa9226c7510fe0f745a..31b3161e3994a7c78dba071d3978b379ae52e9ed 100644
--- a/chrome/browser/extensions/extension_preference_api.cc
+++ b/chrome/browser/extensions/extension_preference_api.cc
@@ -29,8 +29,15 @@
 namespace {
 
 struct PrefMappingEntry {
+  // Name of the preference referenced by extension_api.json.
   const char* extension_pref;
+
+  // Name of the preference in the PrefStores.
   const char* browser_pref;
+
+  // Permission required to access this preference.
+  // Use ExtensionAPIPermission::kInvalid for |permission| to express that no
+  // permission is necessary.
   ExtensionAPIPermission::ID permission;
 };