Fix handling of external protocols with PlzNavigate.

third_party/WebKit/Source/platform/weborigin/SchemeRegistry.cpp

Index: third_party/WebKit/Source/platform/weborigin/SchemeRegistry.cpp
diff --git a/third_party/WebKit/Source/platform/weborigin/SchemeRegistry.cpp b/third_party/WebKit/Source/platform/weborigin/SchemeRegistry.cpp
index a49e0ddbed53969c56fc5916a1b93dd6c470ed96..6490b2f20571593b64f8d1e57ce9cdef9bc3f00d 100644
--- a/third_party/WebKit/Source/platform/weborigin/SchemeRegistry.cpp
+++ b/third_party/WebKit/Source/platform/weborigin/SchemeRegistry.cpp
@@ -39,8 +39,7 @@ namespace {
 class URLSchemesRegistry final {
  public:
   URLSchemesRegistry()
-      : emptyDocumentSchemes({"about"}),
-        // For ServiceWorker schemes: HTTP is required because http://localhost
+      : // For ServiceWorker schemes: HTTP is required because http://localhost
         // is considered secure. Additional checks are performed to ensure that
         // other http pages are filtered out.
         serviceWorkerSchemes({"http", "https"}),
@@ -58,6 +57,8 @@ class URLSchemesRegistry final {
       contentSecurityPolicyBypassingSchemes.insert(
           scheme.c_str(), SchemeRegistry::PolicyAreaAll);
     }
+    for (auto& scheme : url::GetEmptyDocumentSchemes())
+      emptyDocumentSchemes.insert(scheme.c_str());
   }
   ~URLSchemesRegistry() = default;
 
@@ -161,11 +162,6 @@ bool SchemeRegistry::shouldTreatURLSchemeAsSecure(const String& scheme) {
   return getURLSchemesRegistry().secureSchemes.contains(scheme);
 }
 
-void SchemeRegistry::registerURLSchemeAsEmptyDocument(const String& scheme) {
-  DCHECK_EQ(scheme, scheme.lower());
-  getMutableURLSchemesRegistry().emptyDocumentSchemes.insert(scheme);
-}
-
 bool SchemeRegistry::shouldLoadURLSchemeAsEmptyDocument(const String& scheme) {
   DCHECK_EQ(scheme, scheme.lower());
   if (scheme.isEmpty())