Preserve original int64 time stamp in ResourceResponse.

Source/platform/network/ResourceResponse.h

Index: Source/platform/network/ResourceResponse.h
diff --git a/Source/platform/network/ResourceResponse.h b/Source/platform/network/ResourceResponse.h
index 5ac1093d88c02041a854e387f6160c965ccd9544..883bfec489df29bc4dd785cfb2085803e5900ec3 100644
--- a/Source/platform/network/ResourceResponse.h
+++ b/Source/platform/network/ResourceResponse.h
@@ -178,6 +178,9 @@ public:
     double responseTime() const { return m_responseTime; }
     void setResponseTime(double responseTime) { m_responseTime = responseTime; }
 
+    int64 originalResponseTime() const { return m_originalResponseTime; }
+    void setOriginalResponseTime(int64 originalResponseTime) { m_originalResponseTime = originalResponseTime; }
+
     const AtomicString& remoteIPAddress() const { return m_remoteIPAddress; }
     void setRemoteIPAddress(const AtomicString& value) { m_remoteIPAddress = value; }
 
@@ -282,6 +285,10 @@ private:
     // responses, this time could be "far" in the past.
     double m_responseTime;
 
+    // The conversion to the double value in |m_responseTime| is lossy.
+    // This preserves the original response time stamp.
+    int64 m_originalResponseTime;
+
     // Remote IP address of the socket which fetched this resource.
     AtomicString m_remoteIPAddress;
 
@@ -330,6 +337,7 @@ public:
     WebServiceWorkerResponseType m_serviceWorkerResponseType;
     KURL m_originalURLViaServiceWorker;
     double m_responseTime;
+    int64 m_originalResponseTime;
     String m_remoteIPAddress;
     unsigned short m_remotePort;
     String m_downloadedFilePath;