Exempt internal requests from our custom tampering

None of the current hooks we have need to tamper with page using
the internal `chrome://` pages, and only brave_webtorrent needs
the extension scheme.

browser/net/brave_request_handler.cc

@@ -25,6 +25,8 @@
 #include "components/prefs/pref_service.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/common/url_constants.h"
+#include "extensions/common/constants.h"
 
 #if BUILDFLAG(ENABLE_BRAVE_REFERRALS)
 #include "brave/browser/net/brave_referrals_network_delegate_helper.h"
@@ -42,6 +44,12 @@
 #include "brave/browser/net/brave_translate_redirect_network_delegate_helper.h"
 #endif
 
+static bool IsInternalScheme(std::shared_ptr<brave::BraveRequestInfo> ctx) {
+  DCHECK(ctx);
+  return ctx->request_url.SchemeIs(extensions::kExtensionScheme) ||
+         ctx->request_url.SchemeIs(content::kChromeUIScheme);
+}
+
 BraveRequestHandler::BraveRequestHandler() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   SetupCallbacks();
@@ -125,7 +133,7 @@ int BraveRequestHandler::OnBeforeURLRequest(
     std::shared_ptr<brave::BraveRequestInfo> ctx,
     net::CompletionOnceCallback callback,
     GURL* new_url) {
-  if (before_url_request_callbacks_.empty()) {
+  if (before_url_request_callbacks_.empty() || IsInternalScheme(ctx)) {
     return net::OK;
   }
   SCOPED_UMA_HISTOGRAM_TIMER("Brave.OnBeforeURLRequest_Handler");
@@ -140,7 +148,7 @@ int BraveRequestHandler::OnBeforeStartTransaction(
     std::shared_ptr<brave::BraveRequestInfo> ctx,
     net::CompletionOnceCallback callback,
     net::HttpRequestHeaders* headers) {
-  if (before_start_transaction_callbacks_.empty()) {
+  if (before_start_transaction_callbacks_.empty() || IsInternalScheme(ctx)) {
     return net::OK;
   }
   ctx->event_type = brave::kOnBeforeStartTransaction;
@@ -163,7 +171,9 @@ int BraveRequestHandler::OnHeadersReceived(
         original_response_headers, override_response_headers);
   }
 
-  if (headers_received_callbacks_.empty()) {
+  if (headers_received_callbacks_.empty() &&
+      !ctx->request_url.SchemeIs(content::kChromeUIScheme)) {
+    // Extension scheme not excluded since brave_webtorrent needs it.
     return net::OK;
   }