Add client for background testing of HTTP pipelining.

chrome/browser/net/http_pipelining_compatibility_client.h

Index: chrome/browser/net/http_pipelining_compatibility_client.h
diff --git a/chrome/browser/net/http_pipelining_compatibility_client.h b/chrome/browser/net/http_pipelining_compatibility_client.h
new file mode 100644
index 0000000000000000000000000000000000000000..93c33efb8827f034c78b4377a3a68b60b0e86b66
--- /dev/null
+++ b/chrome/browser/net/http_pipelining_compatibility_client.h
@@ -0,0 +1,125 @@
+// 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 CHROME_BROWSER_NET_HTTP_PIPELINING_COMPATIBILITY_CLIENT_H_
+#define CHROME_BROWSER_NET_HTTP_PIPELINING_COMPATIBILITY_CLIENT_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "base/memory/scoped_vector.h"
+#include "net/base/completion_callback.h"
+#include "net/base/io_buffer.h"
+#include "net/url_request/url_request.h"
+
+namespace chrome_browser_net {
+
+// Class for performing a background test of users' internet connections.

[mmenke, 2012/02/08 15:50:51]

nit:  Internet.  Doesn't really matter, but more we stick to the Google strings
guide in comments, the more likely we are to do the same in user-visible
strings.

[James Simonsen, 2012/02/10 01:28:48]

Done.

+// Fetches a collection of resources on a test server and verifies all were
+// received correctly. This will be used to determine whether or not proxies are
+// interfering with a user's ability to use HTTP pipelining. Results are
+// recorded with UMA.
+//
+// TODO(simonjam): Connect this to something. We should start with a field trial
+// that affects a subset of canary channel users. But first, we need a test
+// server.
+class HttpPipeliningCompatibilityClient {
+ public:
+  struct RequestInfo {
+    std::string filename;  // The path relative to the test server's base_url.
+    std::string expected_response;  // The expected body of the response.
+  };
+
+  enum Status {
+    SUCCESS,
+    REDIRECTED,         // Response was redirected. We won't follow.
+    CERT_ERROR,         // Any certificate problem.
+    BAD_RESPONSE_CODE,  // Any non-200 response.
+    NETWORK_ERROR,      // Any socket error reported by the network layer.
+    TOO_LARGE,          // The response matched, but had extra data on the end.
+    TOO_SMALL,          // The response was shorter than expected, but what we
+                        // got matched.
+    CONTENT_MISMATCH,   // The response didn't match the expected value.
+    BAD_HTTP_VERSION,   // Any version older than HTTP/1.1.
+    STATUS_MAX,
+  };
+
+  HttpPipeliningCompatibilityClient();
+  ~HttpPipeliningCompatibilityClient();
+
+  // Launches the asynchronous URLRequests to fetch the URLs specified by
+  // |requests| combined with |base_url|. |base_url| should match the pattern
+  // "http://host/". |callback| is invoked once all the requests have completed.
+  // URLRequests are initiated in |url_request_context|. Results are recorded to
+  // UMA as they are received.
+  void Start(const std::string& base_url,
+             std::vector<RequestInfo>& requests,
+             const net::CompletionCallback& callback,
+             net::URLRequestContext* url_request_context);
+
+ private:
+  // There is one Request per RequestInfo passed in to Start() above.
+  class Request : public net::URLRequest::Delegate {
+   public:
+    Request(int request_id,
+            const std::string& base_url,
+            const RequestInfo& info,
+            HttpPipeliningCompatibilityClient* client,
+            net::URLRequestContext* url_request_context);
+    virtual ~Request();
+
+    // net::URLRequest::Delegate interface
+    virtual void OnReceivedRedirect(net::URLRequest* request,
+                                    const GURL& new_url,
+                                    bool* defer_redirect) OVERRIDE;
+    virtual void OnSSLCertificateError(net::URLRequest* request,
+                                       const net::SSLInfo& ssl_info,
+                                       bool fatal) OVERRIDE;
+    virtual void OnResponseStarted(net::URLRequest* request) OVERRIDE;
+    virtual void OnReadCompleted(net::URLRequest* request,
+                                 int bytes_read) OVERRIDE;
+
+   private:
+    // Called when a response can be read. Reads bytes into |response_| until it
+    // consumes the entire response or it encounters an error.
+    void DoRead();
+
+    // Called when all bytes have been received. Compares the |response_| to
+    // |info_|'s expected response.
+    void DoReadFinished();
+
+    // Called when this request has determined its result. Returns the result to
+    // the |client_|.
+    void Finished(Status result);
+
+    const int request_id_;
+    net::URLRequest request_;
+    const RequestInfo info_;
+    HttpPipeliningCompatibilityClient* client_;
+    bool finished_;
+    scoped_refptr<net::IOBuffer> read_buffer_;
+    std::string response_;
+  };
+
+  // Called when a Request determines its result. Reports to UMA.
+  void OnRequestFinished(int request_id, Status status);
+
+  // Called when a Request encounters a network error. Reports to UMA.
+  void ReportNetworkError(int request_id, int error_code);
+
+  // Called when a Request determines its HTTP response code. Reports to UMA.
+  void ReportResponseCode(int request_id, int response_code);
+
+  // Returns the full UMA metric name based on |request_id| and |description|.
+  std::string GetMetricName(int request_id, const char* description);
+
+  ScopedVector<Request> requests_;
+  net::CompletionCallback finished_callback_;
+  size_t num_finished_;
+};
+
+}  // namespace chrome_browser_net
+
+#endif  // CHROME_BROWSER_NET_HTTP_PIPELINING_COMPATIBILITY_CLIENT_H_