Add field trial stats for alternate_protocol. The histogram we collected are:

http stats when alternate protocol is available but npn was not negotiated (
which means not usng spdy), and when alternate is available AND spdy is used.

Noticable changes:
1. In http_network_transaction.cc, changed the logic that always parse 
response from server for alternate protocol and remember that in 
HttpAlternateProtocols strucuture. We need to remember this to collect 
stats for servers with alternate protocol support but used http for.
2. In spdy_stream.cc, get rid of the response copy from spdy_stream. This
copy overwrites some early status in response set in http_network_transaction.


TEST=http_network_transaction_unittest.cc
BUG=46689

Review URL: http://codereview.chromium.org/2808010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@50927 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 8 insertions, 1 deletions

diff --git a/net/url_request/url_request.h b/net/url_request/url_request.h
index aff01c7..f770c89 100644
--- a/net/url_request/url_request.h
+++ b/net/url_request/url_request.h
@@ -371,7 +371,8 @@ class URLRequest {
   // Indicate if this response was fetched from disk cache.
   bool was_cached() const { return response_info_.was_cached; }
 
-  // Returns true if the URLRequest was delivered with SPDY.
+  // True if response could use alternate protocol. However, browser will
+  // ingore the alternate protocol if spdy is not enabled.
   bool was_fetched_via_spdy() const {
     return response_info_.was_fetched_via_spdy;
   }
@@ -382,6 +383,12 @@ class URLRequest {
     return response_info_.was_npn_negotiated;
   }
 
+  // Returns true if the URLRequest was delivered when the alertnate protocol
+  // is available.
+  bool was_alternate_protocol_available() const {
+    return response_info_.was_alternate_protocol_available;
+  }
+
   // Returns true if the URLRequest was delivered through a proxy.
   bool was_fetched_via_proxy() const {
     return response_info_.was_fetched_via_proxy;