Clean up dns prefetch code, and also port it.

chrome/browser/net/dns_host_info_unittest.cc

Index: chrome/browser/net/dns_host_info_unittest.cc
diff --git a/chrome/browser/net/dns_host_info_unittest.cc b/chrome/browser/net/dns_host_info_unittest.cc
index c279804b6f1d42aae1a5d59aa3d5f67fcc53c6ab..a079716c2e9ef5cf42c164c3474c511ddb89e829 100644
--- a/chrome/browser/net/dns_host_info_unittest.cc
+++ b/chrome/browser/net/dns_host_info_unittest.cc
@@ -41,8 +41,7 @@ TEST(DnsHostInfoTest, StateChangeTest) {
   EXPECT_FALSE(info.NeedsDnsUpdate(hostname1))
     << "update needed after being queued";
   info.SetAssignedState();
-  EXPECT_FALSE(info.NeedsDnsUpdate(hostname1))
-    << "update needed while assigned to slave";
+  EXPECT_FALSE(info.NeedsDnsUpdate(hostname1));
   info.SetFoundState();
   EXPECT_FALSE(info.NeedsDnsUpdate(hostname1))
     << "default expiration time is TOOOOO short";
@@ -64,8 +63,7 @@ TEST(DnsHostInfoTest, StateChangeTest) {
   // be found.  We'll sleep for a while, and then come back with not-found.
   info.SetQueuedState(DnsHostInfo::UNIT_TEST_MOTIVATED);
   info.SetAssignedState();
-  EXPECT_FALSE(info.NeedsDnsUpdate(hostname1))
-    << "update needed while assigned to slave";
+  EXPECT_FALSE(info.NeedsDnsUpdate(hostname1));
   // Greater than minimal expected network latency on DNS lookup.
   PlatformThread::Sleep(25);
   info.SetNoSuchNameState();