electron/patches/chromium/feat_allow_enabling_extensions_on_custom_protocols.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Niklas Wenzel <dev@nikwen.de>
Date: Wed, 25 Feb 2026 16:24:03 +0100
Subject: feat: allow enabling extensions on custom protocols

This allows us to use Chrome extensions on custom protocols.

The patch can't really be upstreamed, unfortunately, because there are
other URLPattern functions that we don't patch that Chrome needs.

Patching those properly would require replacing the bitmask logic in
URLPattern with a more flexible solution. This would be a larger effort
and Chromium might reject it for performance reasons.

See: https://source.chromium.org/chromium/chromium/src/+/main:extensions/common/url_pattern.h;l=53-74;drc=50dbcddad2f8e36ddfcec21d4551f389df425c37

This patch makes it work in the context of Electron.

diff --git a/extensions/browser/api/content_settings/content_settings_helpers.cc b/extensions/browser/api/content_settings/content_settings_helpers.cc
index ea484a282d820da78e8dc1db27ad0ba6e070ac2c..a0e361cf2d2960de4f429a9d37459e26614a17c4 100644
--- a/extensions/browser/api/content_settings/content_settings_helpers.cc
+++ b/extensions/browser/api/content_settings/content_settings_helpers.cc
@@ -37,7 +37,7 @@ ContentSettingsPattern ParseExtensionPattern(std::string_view pattern_str,
                                              std::string* error) {
   const int kAllowedSchemes =
       URLPattern::SCHEME_HTTP | URLPattern::SCHEME_HTTPS |
-      URLPattern::SCHEME_FILE;
+      URLPattern::SCHEME_FILE | URLPattern::SCHEME_ELECTRON_CUSTOM_PROTOCOLS;
   URLPattern url_pattern(kAllowedSchemes);
   URLPattern::ParseResult result = url_pattern.Parse(pattern_str);
   if (result != URLPattern::ParseResult::kSuccess) {
diff --git a/extensions/browser/api/web_request/extension_web_request_event_router.h b/extensions/browser/api/web_request/extension_web_request_event_router.h
index 57ed3cf54b2921df09ad84906b3da7527c6080bb..ffe3a0894c612adaa429a783827c85038d959a95 100644
--- a/extensions/browser/api/web_request/extension_web_request_event_router.h
+++ b/extensions/browser/api/web_request/extension_web_request_event_router.h
@@ -53,7 +53,8 @@ inline constexpr int kWebRequestFilterValidSchemes =
     URLPattern::SCHEME_HTTP | URLPattern::SCHEME_HTTPS |
     URLPattern::SCHEME_FTP | URLPattern::SCHEME_FILE |
     URLPattern::SCHEME_EXTENSION | URLPattern::SCHEME_WS |
-    URLPattern::SCHEME_WSS | URLPattern::SCHEME_UUID_IN_PACKAGE;
+    URLPattern::SCHEME_WSS | URLPattern::SCHEME_UUID_IN_PACKAGE |
+    URLPattern::SCHEME_ELECTRON_CUSTOM_PROTOCOLS;
 
 class WebRequestEventRouter : public KeyedService {
  public:
diff --git a/extensions/common/extension.cc b/extensions/common/extension.cc
index 731994059b8900e7cec46acfb9d17f18c3b8ed89..c32aee04fa1788ae26a0f9a0c5b9d2afb94c84c6 100644
--- a/extensions/common/extension.cc
+++ b/extensions/common/extension.cc
@@ -222,7 +222,8 @@ const int Extension::kValidHostPermissionSchemes =
     URLPattern::SCHEME_CHROMEUI | URLPattern::SCHEME_HTTP |
     URLPattern::SCHEME_HTTPS | URLPattern::SCHEME_FILE |
     URLPattern::SCHEME_FTP | URLPattern::SCHEME_WS | URLPattern::SCHEME_WSS |
-    URLPattern::SCHEME_UUID_IN_PACKAGE;
+    URLPattern::SCHEME_UUID_IN_PACKAGE |
+    URLPattern::SCHEME_ELECTRON_CUSTOM_PROTOCOLS;
 
 //
 // Extension
diff --git a/extensions/common/url_pattern.cc b/extensions/common/url_pattern.cc
index d4328ca22fdeefd3dca88bfe959dfb849705b109..ba24e788d4a2e467d24f6369e2d93ea3b4a0c9d7 100644
--- a/extensions/common/url_pattern.cc
+++ b/extensions/common/url_pattern.cc
@@ -140,6 +140,11 @@ bool URLPattern::IsValidSchemeForExtensions(std::string_view scheme) {
       return true;
     }
   }
+  for (auto& extension_scheme : url::GetExtensionSchemes()) {
+    if (scheme == extension_scheme) {
+      return true;
+    }
+  }
   return false;
 }
 
@@ -401,6 +406,14 @@ bool URLPattern::IsValidScheme(std::string_view scheme) const {
     }
   }
 
+  if (valid_schemes_ & URLPattern::SCHEME_ELECTRON_CUSTOM_PROTOCOLS) {
+    for (auto& extension_scheme : url::GetExtensionSchemes()) {
+      if (scheme == extension_scheme) {
+        return true;
+      }
+    }
+  }
+
   return false;
 }
 
diff --git a/extensions/common/url_pattern.h b/extensions/common/url_pattern.h
index 4d09251b0160644d86682ad3db7c41b50f360e6f..8a626e14eff2d58d8218a7b0df820c6c0522b00f 100644
--- a/extensions/common/url_pattern.h
+++ b/extensions/common/url_pattern.h
@@ -64,6 +64,9 @@ class URLPattern {
     SCHEME_DATA = 1 << 9,
     SCHEME_UUID_IN_PACKAGE = 1 << 10,
 
+    // Represents the schemes returned by url::GetExtensionSchemes().
+    SCHEME_ELECTRON_CUSTOM_PROTOCOLS = 1 << 11,
+
     // IMPORTANT!
     // SCHEME_ALL will match every scheme, including chrome://, chrome-
     // extension://, about:, etc. Because this has lots of security
diff --git a/extensions/common/user_script.cc b/extensions/common/user_script.cc
index f680ef4d31d580a285abe51387e3df043d4458f1..afde40d56d7874aa04ea2b1d881e5cab79fd7661 100644
--- a/extensions/common/user_script.cc
+++ b/extensions/common/user_script.cc
@@ -69,7 +69,8 @@ enum {
   kValidUserScriptSchemes = URLPattern::SCHEME_CHROMEUI |
                             URLPattern::SCHEME_HTTP | URLPattern::SCHEME_HTTPS |
                             URLPattern::SCHEME_FILE | URLPattern::SCHEME_FTP |
-                            URLPattern::SCHEME_UUID_IN_PACKAGE
+                            URLPattern::SCHEME_UUID_IN_PACKAGE |
+                            URLPattern::SCHEME_ELECTRON_CUSTOM_PROTOCOLS
 };
 
 // static
diff --git a/url/url_util.cc b/url/url_util.cc
index 1ee0feaad9be437914b101195e862965fcaccff4..7412af58409285fbe9b426c5b2bb8510d362091c 100644
--- a/url/url_util.cc
+++ b/url/url_util.cc
@@ -135,6 +135,9 @@ struct SchemeRegistry {
   // Embedder schemes that have V8 code cache enabled in js and wasm scripts.
   std::vector<std::string> code_cache_schemes = {};
 
+  // Embedder schemes on which Chrome extensions can be used.
+  std::vector<std::string> extension_schemes = {};
+
   // Schemes with a predefined default custom handler.
   std::vector<SchemeWithHandler> predefined_handler_schemes;
 
@@ -679,6 +682,15 @@ const std::vector<std::string>& GetCodeCacheSchemes() {
   return GetSchemeRegistry().code_cache_schemes;
 }
 
+void AddExtensionScheme(std::string_view new_scheme) {
+  DoAddScheme(new_scheme,
+              &GetSchemeRegistryWithoutLocking()->extension_schemes);
+}
+
+const std::vector<std::string>& GetExtensionSchemes() {
+  return GetSchemeRegistry().extension_schemes;
+}
+
 void AddPredefinedHandlerScheme(std::string_view new_scheme,
                                 std::string_view handler) {
   DoAddSchemeWithHandler(
diff --git a/url/url_util.h b/url/url_util.h
index 6906dd1c903209f3bb6d9ca346e845f1dfeef050..f1928796d5c8a01a51ac9237394bdf6236920998 100644
--- a/url/url_util.h
+++ b/url/url_util.h
@@ -124,6 +124,11 @@ COMPONENT_EXPORT(URL) const std::vector<std::string>& GetEmptyDocumentSchemes();
 COMPONENT_EXPORT(URL) void AddCodeCacheScheme(std::string_view new_scheme);
 COMPONENT_EXPORT(URL) const std::vector<std::string>& GetCodeCacheSchemes();
 
+// Adds an application-defined scheme to the list of schemes on which Chrome
+// extensions can be used.
+COMPONENT_EXPORT(URL) void AddExtensionScheme(std::string_view new_scheme);
+COMPONENT_EXPORT(URL) const std::vector<std::string>& GetExtensionSchemes();
+
 // Adds a scheme with a predefined default handler.
 //
 // This pair of strings must be normalized protocol handler parameters as