[WebSocketExtensionParser] Have Consume.* methods return bool instead of using has_error()

net/websockets/websocket_extension_parser.h

 // Copyright 2013 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 NET_WEBSOCKETS_WEBSOCKET_EXTENSION_PARSER_H_
 #define NET_WEBSOCKETS_WEBSOCKET_EXTENSION_PARSER_H_
 
 #include <string>
 #include <vector>
 
+#include "base/compiler_specific.h"
 #include "base/strings/string_piece.h"
 #include "net/base/net_export.h"
 #include "net/websockets/websocket_extension.h"
 
 namespace net {
 
 class NET_EXPORT_PRIVATE WebSocketExtensionParser {
  public:
   WebSocketExtensionParser();
   ~WebSocketExtensionParser();
 
   // Parses the given string as a Sec-WebSocket-Extensions header value.
   //
   // There must be no newline characters in the input. LWS-concatenation must
   // have already been done before calling this method.
-  void Parse(const char* data, size_t size);
-  void Parse(const std::string& data) {
-    Parse(data.data(), data.size());
+  //
+  // Returns true if the method was successful (no syntax error was found).
+  bool Parse(const char* data, size_t size);
+  bool Parse(const std::string& data) {
+    return Parse(data.data(), data.size());
   }
 
-  // Returns true if the last Parse() method call encountered any syntax error.
-  bool has_error() const { return has_error_; }
   // Returns the result of the last Parse() method call.
   const std::vector<WebSocketExtension>& extensions() const {
     return extensions_;
   }
 
  private:
-  // TODO(tyoshino): Make the following methods return success/fail.
-  void Consume(char c);
-  void ConsumeExtension(WebSocketExtension* extension);
-  void ConsumeExtensionParameter(WebSocketExtension::Parameter* parameter);
-  void ConsumeToken(base::StringPiece* token);
-  void ConsumeQuotedToken(std::string* token);
+  WARN_UNUSED_RESULT bool Consume(char c);
+  WARN_UNUSED_RESULT bool ConsumeExtension(WebSocketExtension* extension);
+  WARN_UNUSED_RESULT bool ConsumeExtensionParameter(
+      WebSocketExtension::Parameter* parameter);
+  WARN_UNUSED_RESULT bool ConsumeToken(base::StringPiece* token);
+  WARN_UNUSED_RESULT bool ConsumeQuotedToken(std::string* token);
   void ConsumeSpaces();
-  bool Lookahead(char c);
-  bool ConsumeIfMatch(char c);
+  WARN_UNUSED_RESULT bool Lookahead(char c);
+  WARN_UNUSED_RESULT bool ConsumeIfMatch(char c);
   size_t UnconsumedBytes() const { return end_ - current_; }
 
   static bool IsControl(char c);
   static bool IsSeparator(char c);
 
   // The current position in the input string.
   const char* current_;
   // The pointer of the end of the input string.
   const char* end_;
-  bool has_error_;
   std::vector<WebSocketExtension> extensions_;
 
   DISALLOW_COPY_AND_ASSIGN(WebSocketExtensionParser);
 };
 
 }  // namespace net
 
 #endif  // NET_WEBSOCKETS_WEBSOCKET_EXTENSION_PARSER_H_