Use custom net errors in ExtensionNavigationThrottle.

extensions/browser/extension_navigation_throttle.cc

Index: extensions/browser/extension_navigation_throttle.cc
diff --git a/extensions/browser/extension_navigation_throttle.cc b/extensions/browser/extension_navigation_throttle.cc
index 1d4a17d4954c92964c5e494edf747e706c114139..033de4326a22ca89e5f0ccf2243282654068d789 100644
--- a/extensions/browser/extension_navigation_throttle.cc
+++ b/extensions/browser/extension_navigation_throttle.cc
@@ -56,15 +56,12 @@ ExtensionNavigationThrottle::WillStartOrRedirectRequest() {
   } else {
     // If the navigation is not to a chrome-extension resource, no need to
     // perform any more checks; it's outside of the purview of this throttle.
-    return content::NavigationThrottle::PROCEED;
+    return {PROCEED};
   }
 
   // If the navigation is to an unknown or disabled extension, block it.
-  if (!target_extension) {
-    // TODO(nick): This yields an unsatisfying error page; use a different error
-    // code once that's supported. https://crbug.com/649869
-    return content::NavigationThrottle::BLOCK_REQUEST;
-  }
+  if (!target_extension)
+    return {BLOCK_REQUEST, net::ERR_FILE_NOT_FOUND};
 
   if (navigation_handle()->IsInMainFrame()) {
     // Block top-level navigations to blob: or filesystem: URLs with extension
@@ -80,7 +77,7 @@ ExtensionNavigationThrottle::WillStartOrRedirectRequest() {
           target_extension->permissions_data()->HasAPIPermission(
               APIPermission::kWebView);
       if (!has_webview_permission)
-        return content::NavigationThrottle::CANCEL;
+        return {CANCEL};
     }
 
     guest_view::GuestViewBase* guest =
@@ -106,7 +103,7 @@ ExtensionNavigationThrottle::WillStartOrRedirectRequest() {
           is_guest, target_extension, owner_extension, partition_id, url.path(),
           navigation_handle()->GetPageTransition(), &allowed);
       if (!allowed)
-        return content::NavigationThrottle::BLOCK_REQUEST;
+        return {BLOCK_REQUEST, net::ERR_ACCESS_DENIED};
     }
 
     // Platform apps should only load in app windows, or guest views; never in
@@ -119,11 +116,11 @@ ExtensionNavigationThrottle::WillStartOrRedirectRequest() {
         case VIEW_TYPE_PANEL:
           break;
         default:
-          return content::NavigationThrottle::CANCEL;
+          return {CANCEL};
       }
     }
 
-    return content::NavigationThrottle::PROCEED;
+    return {PROCEED};
   }
 
   // This is a subframe navigation to a |target_extension| resource.
@@ -158,12 +155,12 @@ ExtensionNavigationThrottle::WillStartOrRedirectRequest() {
   if (external_ancestor) {
     // Cancel navigations to nested URLs, to match the main frame behavior.
     if (!url_has_extension_scheme)
-      return content::NavigationThrottle::CANCEL;
+      return {CANCEL};
 
     // |url| must be in the manifest's "web_accessible_resources" section.
     if (!WebAccessibleResourcesInfo::IsResourceWebAccessible(target_extension,
                                                              url.path()))
-      return content::NavigationThrottle::BLOCK_REQUEST;
+      return {BLOCK_REQUEST, net::ERR_ACCESS_DENIED};
 
     // A platform app may not be loaded in an <iframe> by another origin.
     //
@@ -172,17 +169,17 @@ ExtensionNavigationThrottle::WillStartOrRedirectRequest() {
     // Security Policy. But CSP is incapable of blocking the chrome-extension
     // scheme. Thus, this case must be handled specially here.
     if (target_extension->is_platform_app())
-      return content::NavigationThrottle::CANCEL;
+      return {CANCEL};
 
     // A platform app may not load another extension in an <iframe>.
     const Extension* parent_extension =
         registry->enabled_extensions().GetExtensionOrAppByURL(
             parent->GetSiteInstance()->GetSiteURL());
     if (parent_extension && parent_extension->is_platform_app())
-      return content::NavigationThrottle::BLOCK_REQUEST;
+      return {BLOCK_REQUEST, net::ERR_BLOCKED_BY_CLIENT};
   }
 
-  return content::NavigationThrottle::PROCEED;
+  return {PROCEED};
 }
 
 content::NavigationThrottle::ThrottleCheckResult
@@ -196,7 +193,7 @@ ExtensionNavigationThrottle::WillRedirectRequest() {
   if (result.action() == BLOCK_REQUEST) {
     // BLOCK_REQUEST is on redirect does not work without PlzNavigate, so
     // translate these errors into CANCEL.
-    return CANCEL;
+    return {CANCEL};
   }
   return result;
 }