Refactor DNS A/B experient, and add test of congestion time limits

I added another option in the DNS experiment: user 2 seconds or 500ms
for the congestion limit (that causes pre-resolutions to be discarded
from the queue.

The code in browser_main.cc was getting toooo large, so I pulled all
the experiment code into dns_global.cc.

BUG=15479

r=eroman
Review URL: http://codereview.chromium.org/147215

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@19464 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 24 insertions, 9 deletions

diff --git a/chrome/browser/net/dns_master_unittest.cc b/chrome/browser/net/dns_master_unittest.cc
index da720fe..921b43b 100644
--- a/chrome/browser/net/dns_master_unittest.cc
+++ b/chrome/browser/net/dns_master_unittest.cc
@@ -60,6 +60,8 @@ class DnsMasterTest : public testing::Test {
  public:
   DnsMasterTest()
       : mapper_(new net::RuleBasedHostMapper()),
+        default_max_queueing_delay_(TimeDelta::FromMilliseconds(
+            DnsPrefetcherInit::kMaxQueueingDelayMs)),
         scoped_mapper_(mapper_.get()) {
   }
 
@@ -84,6 +86,10 @@ class DnsMasterTest : public testing::Test {
 
   scoped_refptr<net::RuleBasedHostMapper> mapper_;
 
+  // Shorthand to access TimeDelta of DnsPrefetcherInit::kMaxQueueingDelayMs.
+  // (It would be a static constant... except style rules preclude that :-/ ).
+  const TimeDelta default_max_queueing_delay_;
+
  private:
   MessageLoop loop;
   net::ScopedHostMapper scoped_mapper_;
@@ -163,13 +169,15 @@ TEST_F(DnsMasterTest, OsCachesLookupsTest) {
 
 TEST_F(DnsMasterTest, StartupShutdownTest) {
   scoped_refptr<DnsMaster> testing_master = new DnsMaster(new net::HostResolver,
-      MessageLoop::current(), DnsPrefetcherInit::kMaxConcurrentLookups);
+      MessageLoop::current(), default_max_queueing_delay_,
+      DnsPrefetcherInit::kMaxConcurrentLookups);
   testing_master->Shutdown();
 }
 
 TEST_F(DnsMasterTest, BenefitLookupTest) {
   scoped_refptr<DnsMaster> testing_master = new DnsMaster(new net::HostResolver,
-      MessageLoop::current(), DnsPrefetcherInit::kMaxConcurrentLookups);
+      MessageLoop::current(), default_max_queueing_delay_,
+      DnsPrefetcherInit::kMaxConcurrentLookups);
 
   std::string goog("www.google.com"),
     goog2("gmail.google.com.com"),
@@ -232,7 +240,8 @@ TEST_F(DnsMasterTest, ShutdownWhenResolutionIsPendingTest) {
   net::ScopedHostMapper scoped_mapper(mapper.get());
 
   scoped_refptr<DnsMaster> testing_master = new DnsMaster(new net::HostResolver,
-      MessageLoop::current(), DnsPrefetcherInit::kMaxConcurrentLookups);
+      MessageLoop::current(), default_max_queueing_delay_,
+      DnsPrefetcherInit::kMaxConcurrentLookups);
 
   std::string localhost("127.0.0.1");
   NameList names;
@@ -255,7 +264,8 @@ TEST_F(DnsMasterTest, ShutdownWhenResolutionIsPendingTest) {
 
 TEST_F(DnsMasterTest, SingleLookupTest) {
   scoped_refptr<DnsMaster> testing_master = new DnsMaster(new net::HostResolver,
-      MessageLoop::current(), DnsPrefetcherInit::kMaxConcurrentLookups);
+      MessageLoop::current(), default_max_queueing_delay_,
+      DnsPrefetcherInit::kMaxConcurrentLookups);
 
   std::string goog("www.google.com");
 
@@ -284,7 +294,8 @@ TEST_F(DnsMasterTest, ConcurrentLookupTest) {
   mapper_->AddSimulatedFailure("*.notfound");
 
   scoped_refptr<DnsMaster> testing_master = new DnsMaster(new net::HostResolver,
-      MessageLoop::current(), DnsPrefetcherInit::kMaxConcurrentLookups);
+      MessageLoop::current(), default_max_queueing_delay_,
+      DnsPrefetcherInit::kMaxConcurrentLookups);
 
   std::string goog("www.google.com"),
     goog2("gmail.google.com.com"),
@@ -338,7 +349,8 @@ TEST_F(DnsMasterTest, DISABLED_MassiveConcurrentLookupTest) {
   mapper_->AddSimulatedFailure("*.notfound");
 
   scoped_refptr<DnsMaster> testing_master = new DnsMaster(new net::HostResolver,
-      MessageLoop::current(), DnsPrefetcherInit::kMaxConcurrentLookups);
+      MessageLoop::current(), default_max_queueing_delay_,
+      DnsPrefetcherInit::kMaxConcurrentLookups);
 
   NameList names;
   for (int i = 0; i < 100; i++)
@@ -442,7 +454,8 @@ int GetLatencyFromSerialization(const std::string& motivation,
 // Make sure nil referral lists really have no entries, and no latency listed.
 TEST_F(DnsMasterTest, ReferrerSerializationNilTest) {
   scoped_refptr<DnsMaster> master = new DnsMaster(new net::HostResolver,
-      MessageLoop::current(), DnsPrefetcherInit::kMaxConcurrentLookups);
+      MessageLoop::current(), default_max_queueing_delay_,
+      DnsPrefetcherInit::kMaxConcurrentLookups);
   ListValue referral_list;
   master->SerializeReferrers(&referral_list);
   EXPECT_EQ(0U, referral_list.GetSize());
@@ -457,7 +470,8 @@ TEST_F(DnsMasterTest, ReferrerSerializationNilTest) {
 // serialization without being changed.
 TEST_F(DnsMasterTest, ReferrerSerializationSingleReferrerTest) {
   scoped_refptr<DnsMaster> master = new DnsMaster(new net::HostResolver,
-      MessageLoop::current(), DnsPrefetcherInit::kMaxConcurrentLookups);
+      MessageLoop::current(), default_max_queueing_delay_,
+      DnsPrefetcherInit::kMaxConcurrentLookups);
   std::string motivation_hostname = "www.google.com";
   std::string subresource_hostname = "icons.google.com";
   const int kLatency = 3;
@@ -481,7 +495,8 @@ TEST_F(DnsMasterTest, ReferrerSerializationSingleReferrerTest) {
 // Make sure the Trim() functionality works as expected.
 TEST_F(DnsMasterTest, ReferrerSerializationTrimTest) {
   scoped_refptr<DnsMaster> master = new DnsMaster(new net::HostResolver,
-      MessageLoop::current(), DnsPrefetcherInit::kMaxConcurrentLookups);
+      MessageLoop::current(), default_max_queueing_delay_,
+      DnsPrefetcherInit::kMaxConcurrentLookups);
   std::string motivation_hostname = "www.google.com";
   std::string icon_subresource_hostname = "icons.google.com";
   std::string img_subresource_hostname = "img.google.com";