Headless utility classes for making deterministic protocol handlers

headless/public/util/url_fetcher.h

Index: headless/public/util/url_fetcher.h
diff --git a/headless/public/util/url_fetcher.h b/headless/public/util/url_fetcher.h
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+// Copyright 2016 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 HEADLESS_PUBLIC_UTIL_URL_FETCHER_H_
+#define HEADLESS_PUBLIC_UTIL_URL_FETCHER_H_
+
+#include <stddef.h>
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "net/base/net_errors.h"
+#include "url/gurl.h"
+
+namespace net {
+class HttpRequestHeaders;
+class HttpResponseHeaders;
+}  // namespace net
+
+namespace headless {
+
+// An interface for fetching URLs. Note these are only intended to be used once.
+// TODO(alexclarke): Implement a URLFetcher that can backend onto a URLRequest
+// and hook this up in headless_shell under a flag.
+class URLFetcher {
+ public:
+  URLFetcher() {}
+  virtual ~URLFetcher() {}
+
+  // Interface for reporting the fetch result.
+  class ResultListener {
+   public:
+    ResultListener() {}
+
+    // Informs the listener that the fetch failed.
+    virtual void OnStartError(net::Error error) = 0;
+
+    // Informs the listener that the fetch succeeded and returns the HTTP
+    // headers and the body.  NOTE |body| must be owned by the caller and remain
+    // valid until the fetcher is destroyed,
+    virtual void OnFetchComplete(
+        const std::string& final_url,

[Sami, 2016/08/19 11:54:00]

Could we use GURL for URLs everywhere?

[alex clarke (OOO till 29th), 2016/08/19 12:48:58]

Done.

+        int http_response_code,
+        scoped_refptr<net::HttpResponseHeaders> response_headers,
+        const char* body,
+        size_t body_size) = 0;
+
+    // Helper function which extracts the headers from |response_data| and calls
+    // OnFetchComplete.
+    void OnFetchCompleteExtractHeaders(const std::string& final_url,
+                                       int http_response_code,
+                                       const char* response_data,
+                                       size_t response_data_size);
+
+   protected:
+    virtual ~ResultListener() {}
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(ResultListener);
+  };
+
+  // Instructs the sub-class to fetch the resource.
+  virtual void StartFetch(const GURL& rewritten_url,
+                          const net::HttpRequestHeaders& request_headers,
+                          ResultListener* result_listener) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(URLFetcher);
+};
+
+}  // namespace headless
+
+#endif  // HEADLESS_PUBLIC_UTIL_URL_FETCHER_H_