Hand craft an A/B test of SDCH compression

After we're sure we can do SDCH compression to a given URL, toss
a 50-50 coin each time we have a chance to advertise SDCH, and
either completely avoid advertisement, or advertise (including
the dictionary).  Histogram both compression download times, as
well as the download times for the "completely avoid" case.

http://crbug.com/11236
bug=11236
r=wtc,openvcdiff
Review URL: http://codereview.chromium.org/100004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@15010 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 24 insertions, 2 deletions

diff --git a/net/base/sdch_manager.cc b/net/base/sdch_manager.cc
index c6bf950..1ea9e89 100644
--- a/net/base/sdch_manager.cc
+++ b/net/base/sdch_manager.cc
@@ -85,6 +85,7 @@ SdchManager::~SdchManager() {
 void SdchManager::BlacklistDomain(const GURL& url) {
   if (!global_ )
     return;
+  global_->SetAllowLatencyExperiment(url, false);
 
   std::string domain(StringToLowerASCII(url.host()));
   int count = global_->blacklisted_domains_[domain];
@@ -104,6 +105,7 @@ void SdchManager::BlacklistDomain(const GURL& url) {
 void SdchManager::BlacklistDomainForever(const GURL& url) {
   if (!global_ )
     return;
+  global_->SetAllowLatencyExperiment(url, false);
 
   std::string domain(StringToLowerASCII(url.host()));
   global_->exponential_blacklist_count[domain] = INT_MAX;
@@ -331,8 +333,8 @@ void SdchManager::GenerateHash(const std::string& dictionary_text,
   UrlSafeBase64Encode(first_48_bits, client_hash);
   UrlSafeBase64Encode(second_48_bits, server_hash);
 
-  DCHECK(server_hash->length() == 8);
-  DCHECK(client_hash->length() == 8);
+  DCHECK_EQ(server_hash->length(), 8u);
+  DCHECK_EQ(client_hash->length(), 8u);
 }
 
 // static
@@ -507,3 +509,23 @@ bool SdchManager::Dictionary::DomainMatch(const GURL& gurl,
   // TODO(jar): This is not precisely a domain match definition.
   return gurl.DomainIs(restriction.data(), restriction.size());
 }
+
+//------------------------------------------------------------------------------
+// Methods for supporting latency experiments.
+
+bool SdchManager::AllowLatencyExperiment(const GURL& url) const {
+  return allow_latency_experiment_.end() !=
+      allow_latency_experiment_.find(url.host());
+}
+
+void SdchManager::SetAllowLatencyExperiment(const GURL& url, bool enable) {
+  if (enable) {
+    allow_latency_experiment_.insert(url.host());
+    return;
+  }
+  ExperimentSet::iterator it = allow_latency_experiment_.find(url.host());
+  if (allow_latency_experiment_.end() == it)
+    return;  // It was already erased, or never allowed.
+  SdchErrorRecovery(LATENCY_TEST_DISALLOWED);
+  allow_latency_experiment_.erase(it);
+}