Fix handling of external protocols with PlzNavigate.

content/public/common/content_client.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_COMMON_CONTENT_CLIENT_H_
 #define CONTENT_PUBLIC_COMMON_CONTENT_CLIENT_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 89 matching lines @@
   // startup sequence.
   struct Schemes {
     Schemes();
     ~Schemes();
     std::vector<std::string> standard_schemes;
     std::vector<std::string> referrer_schemes;
     std::vector<std::string> savable_schemes;
     // Additional schemes that should be allowed to register service workers.
     // Only secure and trustworthy schemes should be added.
     std::vector<std::string> service_worker_schemes;
-    // For the following three, see the documentation in WebSecurityPolicy.
+    // Registers a URL scheme to be treated as a local scheme (i.e., with the
+    // same security rules as those applied to "file" URLs). This means that
+    // normal pages cannot link to or access URLs of this scheme.
     std::vector<std::string> local_schemes;
+    // Registers a URL scheme to be treated as a noAccess scheme. This means
+    // that pages loaded with this URL scheme always have an opaque origin.
     std::vector<std::string> no_access_schemes;
+    // Registers a non-HTTP URL scheme which can be sent CORS requests.
     std::vector<std::string> cors_enabled_schemes;
+    // Registers a URL scheme whose resources can be loaded regardless of a
+    // page's Content Security Policy.
     std::vector<std::string> csp_bypassing_schemes;
     // See https://www.w3.org/TR/powerful-features/#is-origin-trustworthy.
     std::vector<std::string> secure_schemes;
     std::vector<GURL> secure_origins;
+    // Registers a URL scheme as strictly empty documents, allowing them to
+    // commit synchronously.
+    std::vector<std::string> empty_document_schemes;
   };
 
   virtual void AddAdditionalSchemes(Schemes* schemes) {}
 
   // Returns whether the given message should be sent in a swapped out renderer.
   virtual bool CanSendWhileSwappedOut(const IPC::Message* message);
 
   // Returns a string describing the embedder product name and version,
   // of the form "productname/version", with no other slashes.
   // Used as part of the user agent string.
@@ skipping 69 matching lines @@
   ContentGpuClient* gpu_;
   // The embedder API for participating in renderer logic.
   ContentRendererClient* renderer_;
   // The embedder API for participating in utility logic.
   ContentUtilityClient* utility_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_CONTENT_CLIENT_H_