Use int64 time stamp when storing metadata to the HTTP cache.

content/common/view_messages.h

 // 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.
 
 // IPC messages for page rendering.
 // Multiply-included message file, hence no include guard.
 
 #include "base/memory/shared_memory.h"
 #include "base/process/process.h"
 #include "base/strings/string16.h"
@@ skipping 1449 matching lines @@
                             GURL /* URL of requestor */,
                             std::string /* signed public key and challenge */)
 
 // Message sent from the renderer to the browser to request that the browser
 // cache |data| associated with |url|.
 IPC_MESSAGE_CONTROL3(ViewHostMsg_DidGenerateCacheableMetadata,
                      GURL /* url */,
                      double /* expected_response_time */,
                      std::vector<char> /* data */)
 
+// Message sent from the renderer to the browser to request that the browser
+// cache |data| associated with |url| and |expected_response_time|.
+IPC_MESSAGE_CONTROL3(
+    ViewHostMsg_DidGenerateCacheableMetadataOriginalResponseTime,
+    GURL /* url */,
+    int64 /* expected_response_time */,

[davidben, 2015/02/18 18:50:45]

base::Time? We don't seem to have issues putting a base::Time in an IPC, going
by codesearch.

+    std::vector<char> /* data */)
+
 // Register a new handler for URL requests with the given scheme.
 IPC_MESSAGE_ROUTED4(ViewHostMsg_RegisterProtocolHandler,
                     std::string /* scheme */,
                     GURL /* url */,
                     base::string16 /* title */,
                     bool /* user_gesture */)
 
 // Unregister the registered handler for URL requests with the given scheme.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_UnregisterProtocolHandler,
                     std::string /* scheme */,
@@ skipping 163 matching lines @@
 // cached by the OS. Please see RenderMessageFilter::OnPreCacheFontCharacters
 // for details.
 IPC_SYNC_MESSAGE_CONTROL2_0(ViewHostMsg_PreCacheFontCharacters,
                             LOGFONT /* font_data */,
                             base::string16 /* characters */)
 #endif
 
 // Adding a new message? Stick to the sort order above: first platform
 // independent ViewMsg, then ifdefs for platform specific ViewMsg, then platform
 // independent ViewHostMsg, then ifdefs for platform specific ViewHostMsg.