Feature to disable field trials in old versions of Chromium. Field trials...

net/disk_cache/backend_impl.cc

Index: net/disk_cache/backend_impl.cc
===================================================================
--- net/disk_cache/backend_impl.cc	(revision 71810)
+++ net/disk_cache/backend_impl.cc	(working copy)
@@ -174,13 +174,16 @@
 
   // Field trials involve static objects so we have to do this only once.
   first = false;
+  std::string group1 = base::StringPrintf("CacheSizeGroup_%d", size_group);
+  int totalProbability = 10;
   scoped_refptr<base::FieldTrial> trial1(
-      new base::FieldTrial("CacheSize", 10));
-  std::string group1 = base::StringPrintf("CacheSizeGroup_%d", size_group);
-  trial1->AppendGroup(group1, base::FieldTrial::kAllRemainingProbability);
+      new base::FieldTrial("CacheSize", totalProbability, group1, 2011, 6, 30));
+  trial1->AppendGroup(group1, totalProbability);
 
+  // After June 30, 2011 builds, it will always be in default group.
   scoped_refptr<base::FieldTrial> trial2(
-      new base::FieldTrial("CacheThrottle", 100));
+      new base::FieldTrial(
+          "CacheThrottle", 100, "CacheThrottle_Default", 2011, 6, 30));
   int group2a = trial2->AppendGroup("CacheThrottle_On", 10);  // 10 % in.
   trial2->AppendGroup("CacheThrottle_Off", 10);  // 10 % control.