Remove measurement of DNS resolution waste from not always performing AF_UNSPEC

lookups. The measurement code has been in long enough to draw conclusions.
This is simply a revert of r151312 and r151710.

BUG=139811


Review URL: https://chromiumcodereview.appspot.com/11734020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@175469 0039d316-1c4b-4281-b951-d872f2087c98

net/base/host_resolver_impl.cc

@@ -1725,45 +1725,6 @@ int HostResolverImpl::Resolve(const RequestInfo& info,
   JobMap::iterator jobit = jobs_.find(key);
   Job* job;
   if (jobit == jobs_.end()) {
-    // If we couldn't find the desired address family, check to see if the
-    // other family is in the cache or another job, which indicates waste,
-    // and we should fix crbug.com/139811.
-    {
-      bool ipv4 = key.address_family == ADDRESS_FAMILY_IPV4;
-      Key other_family_key = key;
-      other_family_key.address_family = ipv4 ?
-          ADDRESS_FAMILY_UNSPECIFIED : ADDRESS_FAMILY_IPV4;
-      bool found_other_family_cache = false;
-      bool found_other_family_job = false;
-      if (default_address_family_ == ADDRESS_FAMILY_UNSPECIFIED) {
-        found_other_family_cache = cache_.get() &&
-            cache_->Lookup(other_family_key, base::TimeTicks::Now()) != NULL;
-        if (!found_other_family_cache)
-          found_other_family_job = jobs_.count(other_family_key) > 0;
-      }
-      enum {  // Used in UMA_HISTOGRAM_ENUMERATION.
-        AF_WASTE_IPV4_ONLY,
-        AF_WASTE_CACHE_IPV4,
-        AF_WASTE_CACHE_UNSPEC,
-        AF_WASTE_JOB_IPV4,
-        AF_WASTE_JOB_UNSPEC,
-        AF_WASTE_NONE_IPV4,
-        AF_WASTE_NONE_UNSPEC,
-        AF_WASTE_MAX,  // Bounding value.
-      } category = AF_WASTE_MAX;
-      if (default_address_family_ != ADDRESS_FAMILY_UNSPECIFIED) {
-        category = AF_WASTE_IPV4_ONLY;
-      } else if (found_other_family_cache) {
-        category = ipv4 ? AF_WASTE_CACHE_IPV4 : AF_WASTE_CACHE_UNSPEC;
-      } else if (found_other_family_job) {
-        category = ipv4 ? AF_WASTE_JOB_IPV4 : AF_WASTE_JOB_UNSPEC;
-      } else {
-        category = ipv4 ? AF_WASTE_NONE_IPV4 : AF_WASTE_NONE_UNSPEC;
-      }
-      UMA_HISTOGRAM_ENUMERATION("DNS.ResolveUnspecWaste", category,
-                                AF_WASTE_MAX);
-    }
-
     job = new Job(weak_ptr_factory_.GetWeakPtr(), key, info.priority(),
                   request_net_log);
     job->Schedule();