Re-enable SPDY *HOLDBACK* field trials.

It had turned off after June 30, 2011 builds. Extend to 2013. This is useful to gather SPDY over SSL vs HTTP over SSL metrics, which have disappeared now :(

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/7946009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@102170 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chrome_browser_main.cc

@@ -858,10 +858,10 @@ void ChromeBrowserMainParts::SpdyFieldTrial() {
     const base::FieldTrial::Probability kSpdyDivisor = 100;
     base::FieldTrial::Probability npnhttp_probability = 5;
 
-    // After June 30, 2011 builds, it will always be in default group.
+    // After June 30, 2013 builds, it will always be in default group.
     scoped_refptr<base::FieldTrial> trial(
         new base::FieldTrial(
-            "SpdyImpact", kSpdyDivisor, "npn_with_spdy", 2011, 6, 30));
+            "SpdyImpact", kSpdyDivisor, "npn_with_spdy", 2013, 6, 30));
 
     // npn with spdy support is the default.
     int npn_spdy_grp = trial->kDefaultGroupNumber;
@@ -892,11 +892,11 @@ void ChromeBrowserMainParts::SpdyFieldTrial() {
   const base::FieldTrial::Probability kSpdyCwndMin16 = 20;  // no less than 16
   const base::FieldTrial::Probability kSpdyCwndMin10 = 20;  // no less than 10
 
-  // After June 30, 2011 builds, it will always be in default group
+  // After June 30, 2013 builds, it will always be in default group
   // (cwndDynamic).
   scoped_refptr<base::FieldTrial> trial(
       new base::FieldTrial(
-          "SpdyCwnd", kSpdyCwndDivisor, "cwndDynamic", 2011, 6, 30));
+          "SpdyCwnd", kSpdyCwndDivisor, "cwndDynamic", 2013, 6, 30));
 
   trial->AppendGroup("cwnd10", kSpdyCwnd10);
   trial->AppendGroup("cwnd16", kSpdyCwnd16);