Correct latency histograms for SDCH encoding

Add a boolean to indicate if the request_time_ was
set via a call to Now(), vs unpickling from the
cache, so that cached results can be excluded from
latency measurements.

bug=1561947

r=darin,rvargas
Review URL: http://codereview.chromium.org/17371

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@7942 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 17 insertions, 2 deletions

diff --git a/net/http/http_cache.cc b/net/http/http_cache.cc
index 2ac62ef..7edc0a8 100644
--- a/net/http/http_cache.cc
+++ b/net/http/http_cache.cc
@@ -1022,6 +1022,7 @@ bool HttpCache::ReadResponseInfo(disk_cache::Entry* disk_entry,
   if (!pickle.ReadInt64(&iter, &time_val))
     return false;
   response_info->request_time = Time::FromInternalValue(time_val);
+  response_info->was_cached = true;  // Set status to show cache resurrection.
 
   // read response-time
   if (!pickle.ReadInt64(&iter, &time_val))
diff --git a/net/http/http_network_transaction.cc b/net/http/http_network_transaction.cc
index 45a9a5e..9d6ed1b 100644
--- a/net/http/http_network_transaction.cc
+++ b/net/http/http_network_transaction.cc
@@ -560,8 +560,10 @@ int HttpNetworkTransaction::DoWriteHeaders() {
 
   // Record our best estimate of the 'request time' as the time when we send
   // out the first bytes of the request headers.
-  if (request_headers_bytes_sent_ == 0)
+  if (request_headers_bytes_sent_ == 0) {
     response_.request_time = Time::Now();
+    response_.was_cached = false;
+  }
 
   const char* buf = request_headers_.data() + request_headers_bytes_sent_;
   int buf_len = static_cast<int>(request_headers_.size() -
diff --git a/net/http/http_response_info.h b/net/http/http_response_info.h
index 80defef..5563ada 100644
--- a/net/http/http_response_info.h
+++ b/net/http/http_response_info.h
@@ -15,6 +15,15 @@ namespace net {
 
 class HttpResponseInfo {
  public:
+  // The following is only defined if the request_time memmber is set.
+  // If this response was resurrected from cache, then this bool is set, and
+  // request_time may corresponds to a time "far" in the past.  Note that
+  // stale content (perhaps un-cacheable) may be fetched from cache subject to
+  // the load flags specified on the request info.  For example, this is done
+  // when a user presses the back button to re-render pages, or at startup, when
+  // reloading previously visited pages (without going over the network).
+  bool was_cached;
+
   // The time at which the request was made that resulted in this response.
   // For cached responses, this time could be "far" in the past.
   base::Time request_time;
diff --git a/net/http/http_transaction_unittest.h b/net/http/http_transaction_unittest.h
index eb2d7bb..ccdb954 100644
--- a/net/http/http_transaction_unittest.h
+++ b/net/http/http_transaction_unittest.h
@@ -7,6 +7,7 @@
 
 #include "net/http/http_transaction.h"
 
+#include <algorithm>
 #include <string>
 
 #include "base/compiler_specific.h"
@@ -212,6 +213,7 @@ class MockNetworkTransaction : public net::HttpTransaction {
     std::replace(header_data.begin(), header_data.end(), '\n', '\0');
 
     response_.request_time = base::Time::Now();
+    response_.was_cached = false;
     response_.response_time = base::Time::Now();
     response_.headers = new net::HttpResponseHeaders(header_data);
     response_.ssl_info.cert_status = t->cert_status;
diff --git a/net/http/http_transaction_winhttp.cc b/net/http/http_transaction_winhttp.cc
index b1ecf2a..06cd391 100644
--- a/net/http/http_transaction_winhttp.cc
+++ b/net/http/http_transaction_winhttp.cc
@@ -172,7 +172,7 @@ class HttpTransactionWinHttp::Session
                                  WINHTTP_FLAG_SECURE_PROTOCOL_TLS1
   };
 
-  Session(ProxyService* proxy_service);
+  explicit Session(ProxyService* proxy_service);
 
   // Opens the primary WinHttp session handle.
   bool Init(const std::string& user_agent);
@@ -1232,6 +1232,7 @@ int HttpTransactionWinHttp::SendRequest() {
   }
 
   response_.request_time = Time::Now();
+  response_.was_cached = false;
 
   DWORD total_size = 0;
   if (request_->upload_data) {