UMA: Add Net.WebSocket.DeflateMode

net/websockets/websocket_deflater.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_DEFLATER_H_
 #define NET_WEBSOCKETS_WEBSOCKET_DEFLATER_H_
 
 #include <deque>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "net/base/net_export.h"
 
 extern "C" struct z_stream_s;
 
 namespace net {
 
 class IOBufferWithSize;
 
 class NET_EXPORT_PRIVATE WebSocketDeflater {
  public:
+  // Do not reorder or remove entries of this enum. The values of them are used
+  // in UMA.
   enum ContextTakeOverMode {
     DO_NOT_TAKE_OVER_CONTEXT,
     TAKE_OVER_CONTEXT,
+    NUM_CONTEXT_TAKEOVER_MODE_TYPES,
   };
 
   explicit WebSocketDeflater(ContextTakeOverMode mode);
   ~WebSocketDeflater();
 
   // Returns true if there is no error and false otherwise.
   // This function must be called exactly once before calling any of
   // following methods.
   // |window_bits| must be between 8 and 15 (both inclusive).
   bool Initialize(int window_bits);
@@ skipping 29 matching lines @@
   std::vector<char> fixed_buffer_;
   // true if bytes were added after last Finish().
   bool are_bytes_added_;
 
   DISALLOW_COPY_AND_ASSIGN(WebSocketDeflater);
 };
 
 }  // namespace net
 
 #endif  // NET_WEBSOCKETS_WEBSOCKET_DEFLATER_H_