Headless: make URLRequestDispatcher aware of navigations

headless/public/util/deterministic_dispatcher.h

Index: headless/public/util/deterministic_dispatcher.h
diff --git a/headless/public/util/deterministic_dispatcher.h b/headless/public/util/deterministic_dispatcher.h
index 0fea383b9cc42e747b8daa65ad1ca3bf0193c649..56c7c7e6390f3204a05377d93592fca673ca0c9e 100644
--- a/headless/public/util/deterministic_dispatcher.h
+++ b/headless/public/util/deterministic_dispatcher.h
@@ -20,8 +20,8 @@ namespace headless {
 
 class ManagedDispatchURLRequestJob;
 
-// The purpose of this class is to queue up calls to OnHeadersComplete and
-// OnStartError and dispatch them in order of URLRequestJob creation. This
+// The purpose of this class is to queue up navigations and calls to
+// OnHeadersComplete / OnStartError and dispatch them in order of creation. This
 // helps make renders deterministic at the cost of slower page loads.
 class DeterministicDispatcher : public URLRequestDispatcher {
  public:
@@ -36,17 +36,34 @@ class DeterministicDispatcher : public URLRequestDispatcher {
   void JobFailed(ManagedDispatchURLRequestJob* job, net::Error error) override;
   void DataReady(ManagedDispatchURLRequestJob* job) override;
   void JobDeleted(ManagedDispatchURLRequestJob* job) override;
+  void NavigationRequested(
+      std::unique_ptr<NavigationRequest> navigation_request) override;
 
  private:
+  void MaybeDispatchNavigationJobLocked();
   void MaybeDispatchJobLocked();
   void MaybeDispatchJobOnIOThreadTask();
+  void NavigationDoneTask();
 
   scoped_refptr<base::SingleThreadTaskRunner> io_thread_task_runner_;
 
   // Protects all members below.
   base::Lock lock_;
 
-  std::deque<ManagedDispatchURLRequestJob*> pending_requests_;
+  // TODO(alexclarke): Use std::variant when c++17 is allowed in chromium.
+  struct Request {
+    Request();
+    explicit Request(ManagedDispatchURLRequestJob* url_request);
+    explicit Request(std::unique_ptr<NavigationRequest> navigation_request);
+    ~Request();
+
+    Request& operator=(Request&& other);
+
+    ManagedDispatchURLRequestJob* url_request;  // NOT OWNED
+    std::unique_ptr<NavigationRequest> navigation_request;
+  };
+
+  std::deque<Request> pending_requests_;
 
   using StatusMap = std::map<ManagedDispatchURLRequestJob*, net::Error>;
   StatusMap ready_status_map_;
@@ -54,6 +71,7 @@ class DeterministicDispatcher : public URLRequestDispatcher {
   // Whether or not a MaybeDispatchJobOnIoThreadTask has been posted on the
   // |io_thread_task_runner_|
   bool dispatch_pending_;
+  bool navigation_in_progress_;
 
   base::WeakPtrFactory<DeterministicDispatcher> weak_ptr_factory_;