Revert of Remove unused HttpClient class.

webrtc/base/httpclient.h

Index: webrtc/base/httpclient.h
diff --git a/webrtc/base/httpclient.h b/webrtc/base/httpclient.h
new file mode 100644
index 0000000000000000000000000000000000000000..569ff04ed83924a5ad0a684db2d96a3ae8245554
--- /dev/null
+++ b/webrtc/base/httpclient.h
@@ -0,0 +1,196 @@
+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_BASE_HTTPCLIENT_H__
+#define WEBRTC_BASE_HTTPCLIENT_H__
+
+#include <memory>
+
+#include "webrtc/base/common.h"
+#include "webrtc/base/httpbase.h"
+#include "webrtc/base/nethelpers.h"
+#include "webrtc/base/proxyinfo.h"
+#include "webrtc/base/sigslot.h"
+#include "webrtc/base/socketaddress.h"
+#include "webrtc/base/socketpool.h"
+
+namespace rtc {
+
+//////////////////////////////////////////////////////////////////////
+// Client-specific http utilities
+//////////////////////////////////////////////////////////////////////
+
+// Write cache-relevant response headers to output stream.  If size is non-null,
+// it contains the length of the output in bytes.  output may be null if only
+// the length is desired.
+bool HttpWriteCacheHeaders(const HttpResponseData* response,
+                           StreamInterface* output, size_t* size);
+// Read cached headers from a stream, and them merge them into the response
+// object using the specified combine operation.
+bool HttpReadCacheHeaders(StreamInterface* input,
+                          HttpResponseData* response,
+                          HttpData::HeaderCombine combine);
+
+//////////////////////////////////////////////////////////////////////
+// HttpClient
+// Implements an HTTP 1.1 client.
+//////////////////////////////////////////////////////////////////////
+
+class DiskCache;
+class HttpClient;
+class IPNetPool;
+
+class SignalThread;
+// What to do:  Define STRICT_HTTP_ERROR=1 in your makefile.  Use HttpError in
+// your code (HttpErrorType should only be used for code that is shared
+// with groups which have not yet migrated).
+#if defined(STRICT_HTTP_ERROR) && STRICT_HTTP_ERROR
+typedef HttpError HttpErrorType;
+#else  // !STRICT_HTTP_ERROR
+typedef int HttpErrorType;
+#endif  // !STRICT_HTTP_ERROR
+
+class HttpClient : private IHttpNotify, public sigslot::has_slots<> {
+public:
+  // If HttpRequestData and HttpResponseData objects are provided, they must
+  // be freed by the caller.  Otherwise, an internal object is allocated.
+  HttpClient(const std::string& agent, StreamPool* pool,
+             HttpTransaction* transaction = NULL);
+  ~HttpClient() override;
+
+  void set_pool(StreamPool* pool) { pool_ = pool; }
+
+  void set_agent(const std::string& agent) { agent_ = agent; }
+  const std::string& agent() const { return agent_; }
+
+  void set_proxy(const ProxyInfo& proxy) { proxy_ = proxy; }
+  const ProxyInfo& proxy() const { return proxy_; }
+
+  // Request retries occur when the connection closes before the beginning of
+  // an http response is received.  In these cases, the http server may have
+  // timed out the keepalive connection before it received our request.  Note
+  // that if a request document cannot be rewound, no retry is made.  The
+  // default is 1.
+  void set_request_retries(size_t retries) { retries_ = retries; }
+  size_t request_retries() const { return retries_; }
+
+  enum RedirectAction { REDIRECT_DEFAULT, REDIRECT_ALWAYS, REDIRECT_NEVER };
+  void set_redirect_action(RedirectAction action) { redirect_action_ = action; }
+  RedirectAction redirect_action() const { return redirect_action_; }
+
+  enum UriForm { URI_DEFAULT, URI_ABSOLUTE, URI_RELATIVE };
+  void set_uri_form(UriForm form) { uri_form_ = form; }
+  UriForm uri_form() const { return uri_form_; }
+
+  void set_cache(DiskCache* cache) { ASSERT(!IsCacheActive()); cache_ = cache; }
+  bool cache_enabled() const { return (NULL != cache_); }
+
+  // reset clears the server, request, and response structures.  It will also
+  // abort an active request.
+  void reset();
+
+  void set_server(const SocketAddress& address);
+  const SocketAddress& server() const { return server_; }
+
+  // Note: in order for HttpClient to retry a POST in response to
+  // an authentication challenge, a redirect response, or socket disconnection,
+  // the request document must support 'replaying' by calling Rewind() on it.
+  HttpTransaction* transaction() { return transaction_; }
+  const HttpTransaction* transaction() const { return transaction_; }
+  HttpRequestData& request() { return transaction_->request; }
+  const HttpRequestData& request() const { return transaction_->request; }
+  HttpResponseData& response() { return transaction_->response; }
+  const HttpResponseData& response() const { return transaction_->response; }
+
+  // convenience methods
+  void prepare_get(const std::string& url);
+  void prepare_post(const std::string& url, const std::string& content_type,
+                    StreamInterface* request_doc);
+
+  // Convert HttpClient to a pull-based I/O model.
+  StreamInterface* GetDocumentStream();
+
+  // After you finish setting up your request, call start.
+  void start();
+
+  // Signalled when the header has finished downloading, before the document
+  // content is processed.  You may change the response document in response
+  // to this signal.  The second parameter indicates whether this is an
+  // intermediate (false) or final (true) header.  An intermediate header is
+  // one that generates another request, such as a redirect or authentication
+  // challenge.  The third parameter indicates the length of the response
+  // document, or else SIZE_UNKNOWN.  Note: Do NOT abort the request in response
+  // to this signal.
+  sigslot::signal3<HttpClient*,bool,size_t> SignalHeaderAvailable;
+  // Signalled when the current request finishes.  On success, err is 0.
+  sigslot::signal2<HttpClient*,HttpErrorType> SignalHttpClientComplete;
+
+protected:
+  void connect();
+  void release();
+
+  bool ShouldRedirect(std::string* location) const;
+
+  bool BeginCacheFile();
+  HttpError WriteCacheHeaders(const std::string& id);
+  void CompleteCacheFile();
+
+  bool CheckCache();
+  HttpError ReadCacheHeaders(const std::string& id, bool override);
+  HttpError ReadCacheBody(const std::string& id);
+
+  bool PrepareValidate();
+  HttpError CompleteValidate();
+
+  HttpError OnHeaderAvailable(bool ignore_data, bool chunked, size_t data_size);
+
+  void StartDNSLookup();
+  void OnResolveResult(AsyncResolverInterface* resolver);
+
+  // IHttpNotify Interface
+  HttpError onHttpHeaderComplete(bool chunked, size_t& data_size) override;
+  void onHttpComplete(HttpMode mode, HttpError err) override;
+  void onHttpClosed(HttpError err) override;
+
+private:
+  enum CacheState { CS_READY, CS_WRITING, CS_READING, CS_VALIDATING };
+  bool IsCacheActive() const { return (cache_state_ > CS_READY); }
+
+  std::string agent_;
+  StreamPool* pool_;
+  HttpBase base_;
+  SocketAddress server_;
+  ProxyInfo proxy_;
+  HttpTransaction* transaction_;
+  bool free_transaction_;
+  size_t retries_, attempt_, redirects_;
+  RedirectAction redirect_action_;
+  UriForm uri_form_;
+  std::unique_ptr<HttpAuthContext> context_;
+  DiskCache* cache_;
+  CacheState cache_state_;
+  AsyncResolverInterface* resolver_;
+};
+
+//////////////////////////////////////////////////////////////////////
+// HttpClientDefault - Default implementation of HttpClient
+//////////////////////////////////////////////////////////////////////
+
+class HttpClientDefault : public ReuseSocketPool, public HttpClient {
+public:
+  HttpClientDefault(SocketFactory* factory, const std::string& agent,
+                    HttpTransaction* transaction = NULL);
+};
+
+//////////////////////////////////////////////////////////////////////
+
+}  // namespace rtc
+
+#endif // WEBRTC_BASE_HTTPCLIENT_H__