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 71223)
+++ net/disk_cache/backend_impl.cc	(working copy)
@@ -174,13 +174,15 @@
 
   // Field trials involve static objects so we have to do this only once.
   first = false;
+  std::string group1 = base::StringPrintf("CacheSizeGroup_%d", size_group);
   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", 10, group1, 2011, 6, 30));
+  trial1->group();

[jar (doing other things), 2011/01/15 20:52:47]

nit: API should not require users to explicitly call group() to finalize.

 
+  // After June 30, 2011 builds, it will always be in defaut 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.