Add a mechanism to disable IPv6.

(1) Adds the ability to specify the address family on a per-request basis.

(2) Exposes a --disable-ipv6 flag to chrome that changes the default address family from AF_UNSPEC to AF_INET (same sort of thing Firefox does).

(3) Changes the backing datastructure for HostCache:EntryMap and HostResolverImpl::JobMap from a "hash_map" to a "std::map". This was for consistency with other code (when I went to add a custom hash trait, I couldn't find any existing code which was using hashmap for custom keys).

(4) Updates about:net-internals to display an address family for the hostcache dump (since it is now a part of the key).

This change is in anticipation of turning off IPv6 host resolving in the PAC utility functions (see bug 24641). But it is also a feature addition.

BUG=24641

TEST=HostCacheTest.AddressFamilyIsPartOfKey
Review URL: http://codereview.chromium.org/302010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@29686 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 14 insertions, 2 deletions

diff --git a/chrome/browser/net/dns_global.cc b/chrome/browser/net/dns_global.cc
index 434208b..c2a89c0 100644
--- a/chrome/browser/net/dns_global.cc
+++ b/chrome/browser/net/dns_global.cc
@@ -22,7 +22,9 @@
 #include "chrome/common/notification_service.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/pref_service.h"
+#include "chrome/common/chrome_switches.h"
 #include "net/base/host_resolver.h"
+#include "net/base/host_resolver_impl.h"
 
 using base::Time;
 using base::TimeDelta;
@@ -477,6 +479,9 @@ net::HostResolver* GetGlobalHostResolver() {
   // Called from UI thread.
   if (!global_host_resolver) {
     global_host_resolver = net::CreateSystemHostResolver();
+
+    if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kDisableIPv6))
+      global_host_resolver->DisableIPv6(true);
   }
   return global_host_resolver;
 }
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index f9413b4..4b47a59 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -237,6 +237,9 @@ const char kShowIcons[]                     = "show-icons";
 // Make Chrome default browser
 const char kMakeDefaultBrowser[]            = "make-default-browser";
 
+// Don't resolve hostnames to IPv6 addresses.
+const char kDisableIPv6[]                   = "disable-ipv6";
+
 // Use a specified proxy server, overrides system settings. This switch only
 // affects HTTP and HTTPS requests.
 const char kProxyServer[]                   = "proxy-server";
diff --git a/chrome/common/chrome_switches.h b/chrome/common/chrome_switches.h
index 9920df2..ded4e54 100644
--- a/chrome/common/chrome_switches.h
+++ b/chrome/common/chrome_switches.h
@@ -81,6 +81,8 @@ extern const char kHideIcons[];
 extern const char kShowIcons[];
 extern const char kMakeDefaultBrowser[];
 
+extern const char kDisableIPv6[];
+
 extern const char kProxyServer[];
 extern const char kNoProxyServer[];
 extern const char kProxyBypassList[];
diff --git a/chrome/test/unit/chrome_test_suite.h b/chrome/test/unit/chrome_test_suite.h
index 52dcc2c..43c7de0 100644
--- a/chrome/test/unit/chrome_test_suite.h
+++ b/chrome/test/unit/chrome_test_suite.h
@@ -36,7 +36,9 @@ class WarningHostResolverProc : public net::HostResolverProc {
  public:
   WarningHostResolverProc() : HostResolverProc(NULL) {}
 
-  virtual int Resolve(const std::string& host, net::AddressList* addrlist) {
+  virtual int Resolve(const std::string& host,
+                      net::AddressFamily address_family,
+                      net::AddressList* addrlist) {
     const char* kLocalHostNames[] = {"localhost", "127.0.0.1"};
     bool local = false;
 
@@ -55,7 +57,7 @@ class WarningHostResolverProc : public net::HostResolverProc {
     // net::RuleBasedHostResolverProc and its AllowDirectLookup method.
     EXPECT_TRUE(local) << "Making external DNS lookup of " << host;
 
-    return ResolveUsingPrevious(host, addrlist);
+    return ResolveUsingPrevious(host, address_family, addrlist);
   }
 };