Improve error message for failing code insertion on about:-URLs

extensions/common/manifest_constants.cc

Index: extensions/common/manifest_constants.cc
diff --git a/extensions/common/manifest_constants.cc b/extensions/common/manifest_constants.cc
index 1c51334cba975b42b1c3a280e75023ef7179c875..8b3e6a4060b3a23bd15c2b6362549fe435b4ec3f 100644
--- a/extensions/common/manifest_constants.cc
+++ b/extensions/common/manifest_constants.cc
@@ -250,6 +250,9 @@ const char kBackgroundPermissionNeeded[] =
     "permission.";
 const char kBackgroundRequiredForPlatformApps[] =
     "Packaged apps must have a background page or background scripts.";
+const char kCannotAccessAboutUrl[] =
+    "Cannot access \"*\" at origin \"*\". Extension must have permission to "
+    "access the frame's origin, and matchAboutBlank must be true.";
 const char kCannotAccessChromeUrl[] = "Cannot access a chrome:// URL";
 const char kCannotAccessExtensionUrl[] =
     "Cannot access a chrome-extension:// URL of different extension";