Moved some functions off ExtensionService into a new file extension_util.

chrome/browser/extensions/extension_prefs.cc

Index: chrome/browser/extensions/extension_prefs.cc
diff --git a/chrome/browser/extensions/extension_prefs.cc b/chrome/browser/extensions/extension_prefs.cc
index 751d5361b5d23b94d3a5263bcd950ee85a8b7c6f..cc04550b05b12b37c0e5aca0d1ab71c33d494eec 100644
--- a/chrome/browser/extensions/extension_prefs.cc
+++ b/chrome/browser/extensions/extension_prefs.cc
@@ -1001,7 +1001,7 @@ bool ExtensionPrefs::IsActive(const std::string& extension_id) {
   return is_active;
 }
 
-bool ExtensionPrefs::IsIncognitoEnabled(const std::string& extension_id) {
+bool ExtensionPrefs::IsIncognitoEnabled(const std::string& extension_id) const {
   return ReadPrefAsBooleanAndReturn(extension_id, kPrefIncognitoEnabled);
 }
 
@@ -1011,7 +1011,7 @@ void ExtensionPrefs::SetIsIncognitoEnabled(const std::string& extension_id,
                       new base::FundamentalValue(enabled));
 }
 
-bool ExtensionPrefs::AllowFileAccess(const std::string& extension_id) {
+bool ExtensionPrefs::AllowFileAccess(const std::string& extension_id) const {
   return ReadPrefAsBooleanAndReturn(extension_id, kPrefAllowFileAccess);
 }