Add three of the six extensions to PAC that Internet Explorer supports.

The following descriptions were taken from <http://blogs.msdn.com/wndp/articles/IPV6_PAC_Extensions_v0_9.aspx> 

---------------------------- 
* myIpAddressEx(): 
Returns a semi-colon delimited string containing all IP addresses for localhost (IPv6 and/or IPv4), or an empty string if unable to resolve localhost to an IP address. 

* dnsResolveEx(host): 
Returns semi-colon delimited string containing IPv6 and IPv4 addresses or an empty string if host is not resolvable. 

* isResolvableEx(): 
Returns TRUE if the host is resolvable to a IPv4 or IPv6 address, FALSE otherwise. 
---------------------------- 

These differ from the vanilla PAC functions in the following ways: 

* myIpAddressEx() returns all the addrsses for localhost (including IPv6 ones), whereas myIpAddress() only returns the first IPv4 one. 
* On failure, myIpAddress() returns "127.0.0.1" whereas on failure myIpAddressEx() returns empty string. 
* dnsResolveEx() returns a list of addresses (including IPV6 ones), whereas dnsResolve() only returns the first IPv4 address. 
* On failure, dnsResolve() returns |null|, whereas on failure dnsResolveEx() returns empty string. 

BUG=25407
TEST=ProxyResolverV8Test.DNSResolutionFailure, ProxyResolverJSBindingsTest.RestrictAddressFamily, ProxyResolverJSBindingsTest.ExFunctionsReturnList
Review URL: http://codereview.chromium.org/333006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@30127 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 363 insertions, 20 deletions

diff --git a/net/base/load_log_event_type_list.h b/net/base/load_log_event_type_list.h
index cd01931..3639003 100644
--- a/net/base/load_log_event_type_list.h
+++ b/net/base/load_log_event_type_list.h
@@ -67,9 +67,15 @@ EVENT_TYPE(PROXY_SERVICE_WAITING_FOR_INIT_PAC)
 // Measures the time taken to execute the "myIpAddress()" javascript binding.
 EVENT_TYPE(PROXY_RESOLVER_V8_MY_IP_ADDRESS)
 
+// Measures the time taken to execute the "myIpAddressEx()" javascript binding.
+EVENT_TYPE(PROXY_RESOLVER_V8_MY_IP_ADDRESS_EX)
+
 // Measures the time taken to execute the "dnsResolve()" javascript binding.
 EVENT_TYPE(PROXY_RESOLVER_V8_DNS_RESOLVE)
 
+// Measures the time taken to execute the "dnsResolveEx()" javascript binding.
+EVENT_TYPE(PROXY_RESOLVER_V8_DNS_RESOLVE_EX)
+
 // ------------------------------------------------------------------------
 // ClientSocketPoolBase::ConnectJob
 // ------------------------------------------------------------------------
diff --git a/net/data/proxy_resolver_v8_unittest/bindings.js b/net/data/proxy_resolver_v8_unittest/bindings.js
index 0e748c1..3026569 100644
--- a/net/data/proxy_resolver_v8_unittest/bindings.js
+++ b/net/data/proxy_resolver_v8_unittest/bindings.js
@@ -35,10 +35,17 @@ function FindProxyForURL(url, host) {
     alert(e);
   }
 
-  // Call myIpAddress() with wonky arguments 
+  // Call myIpAddress() with wonky arguments
   myIpAddress(null);
   myIpAddress(null, null);
 
+  // Call myIpAddressEx() correctly (no arguments).
+  myIpAddressEx();
+
+  // Call dnsResolveEx() (note that isResolvableEx() implicity calls it.)
+  isResolvableEx("is_resolvable");
+  dnsResolveEx("foobar");
+
   return "DIRECT";
 }
 
diff --git a/net/data/proxy_resolver_v8_unittest/dns_fail.js b/net/data/proxy_resolver_v8_unittest/dns_fail.js
new file mode 100644
index 0000000..c71bcc3
--- /dev/null
+++ b/net/data/proxy_resolver_v8_unittest/dns_fail.js
@@ -0,0 +1,27 @@
+// This script should be run in an environment where all DNS resolution are
+// failing. It tests that functions return the expected values.
+//
+// Returns "PROXY success:80" on success.
+function FindProxyForURL(url, host) {
+  try {
+    expectEq("127.0.0.1", myIpAddress());
+    expectEq("", myIpAddressEx());
+
+    expectEq(null, dnsResolve("not-found"));
+    expectEq("", dnsResolveEx("not-found"));
+
+    expectEq(false, isResolvable("not-found"));
+    expectEq(false, isResolvableEx("not-found"));
+
+    return "PROXY success:80";
+  } catch(e) {
+    alert(e);
+    return "PROXY failed:80";
+  }
+}
+
+function expectEq(expected, actual) {
+  if (expected != actual)
+    throw "Expected " + expected + " but was " + actual;
+}
+
diff --git a/net/proxy/proxy_resolver_js_bindings.cc b/net/proxy/proxy_resolver_js_bindings.cc
index f9ea5ae..077e5c6 100644
--- a/net/proxy/proxy_resolver_js_bindings.cc
+++ b/net/proxy/proxy_resolver_js_bindings.cc
@@ -2,6 +2,14 @@
 // source code is governed by a BSD-style license that can be found in the
 // LICENSE file.
 
+#include "build/build_config.h"
+
+#if defined(OS_WIN)
+#include <ws2tcpip.h>
+#else
+#include <netdb.h>
+#endif
+
 #include "net/proxy/proxy_resolver_js_bindings.h"
 
 #include "base/compiler_specific.h"
@@ -97,21 +105,24 @@ class DefaultJSBindings : public ProxyResolverJSBindings {
   }
 
   // Handler for "myIpAddress()". Returns empty string on failure.
+  // TODO(eroman): Perhaps enumerate the interfaces directly, using
+  // getifaddrs().
   virtual std::string MyIpAddress() {
     // DnsResolve("") returns "", so no need to check for failure.
     return DnsResolve(GetHostName());
   }
 
+  // Handler for "myIpAddressEx()". Returns empty string on failure.
+  virtual std::string MyIpAddressEx() {
+    return DnsResolveEx(GetHostName());
+  }
+
   // Handler for "dnsResolve(host)". Returns empty string on failure.
   virtual std::string DnsResolve(const std::string& host) {
-    // TODO(eroman): Should this return our IP address, or fail, or
-    // simply be unspecified (works differently on windows and mac os x).
-    if (host.empty())
-      return std::string();
-
     // Do a sync resolve of the hostname.
-    // Disable IPv6 results. We do this because Internet Explorer does it --
-    // consequently a lot of existing PAC scripts assume they will only get
+    // Disable IPv6 results. We do this because the PAC specification isn't
+    // really IPv6 friendly, and Internet Explorer also restricts to IPv4.
+    // Consequently a lot of existing PAC scripts assume they will only get
     // IPv4 results, and will misbehave if they get an IPv6 result.
     // See http://crbug.com/24641 for more details.
     net::AddressList address_list;
@@ -130,6 +141,31 @@ class DefaultJSBindings : public ProxyResolverJSBindings {
     return net::NetAddressToString(address_list.head());
   }
 
+  // Handler for "dnsResolveEx(host)". Returns empty string on failure.
+  virtual std::string DnsResolveEx(const std::string& host) {
+    // Do a sync resolve of the hostname.
+    net::AddressList address_list;
+    int result = host_resolver_->Resolve(host,
+                                         ADDRESS_FAMILY_UNSPECIFIED,
+                                         &address_list);
+
+    if (result != OK)
+      return std::string();  // Failed.
+
+    // Stringify all of the addresses in the address list, separated
+    // by semicolons.
+    std::string address_list_str;
+    const struct addrinfo* current_address = address_list.head();
+    while (current_address) {
+      if (!address_list_str.empty())
+        address_list_str += ";";
+      address_list_str += net::NetAddressToString(current_address);
+      current_address = current_address->ai_next;
+    }
+
+    return address_list_str;
+  }
+
   // Handler for when an error is encountered. |line_number| may be -1.
   virtual void OnError(int line_number, const std::string& message) {
     if (line_number == -1)
diff --git a/net/proxy/proxy_resolver_js_bindings.h b/net/proxy/proxy_resolver_js_bindings.h
index 6eff69d..03ad61a 100644
--- a/net/proxy/proxy_resolver_js_bindings.h
+++ b/net/proxy/proxy_resolver_js_bindings.h
@@ -24,9 +24,21 @@ class ProxyResolverJSBindings {
   // Handler for "myIpAddress()". Returns empty string on failure.
   virtual std::string MyIpAddress() = 0;
 
+  // Handler for "myIpAddressEx()". Returns empty string on failure.
+  //
+  // This is a Microsoft extension to PAC for IPv6, see:
+  // http://blogs.msdn.com/wndp/articles/IPV6_PAC_Extensions_v0_9.aspx
+  virtual std::string MyIpAddressEx() = 0;
+
   // Handler for "dnsResolve(host)". Returns empty string on failure.
   virtual std::string DnsResolve(const std::string& host) = 0;
 
+  // Handler for "dnsResolveEx(host)". Returns empty string on failure.
+  //
+  // This is a Microsoft extension to PAC for IPv6, see:
+  // http://blogs.msdn.com/wndp/articles/IPV6_PAC_Extensions_v0_9.aspx
+  virtual std::string DnsResolveEx(const std::string& host) = 0;
+
   // Handler for when an error is encountered. |line_number| may be -1
   // if a line number is not applicable to this error.
   virtual void OnError(int line_number, const std::string& error) = 0;
diff --git a/net/proxy/proxy_resolver_js_bindings_unittest.cc b/net/proxy/proxy_resolver_js_bindings_unittest.cc
index b84c829..4e0f6a6 100644
--- a/net/proxy/proxy_resolver_js_bindings_unittest.cc
+++ b/net/proxy/proxy_resolver_js_bindings_unittest.cc
@@ -2,7 +2,16 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "build/build_config.h"
+
+#if defined(OS_WIN)
+#include <ws2tcpip.h>
+#else
+#include <netdb.h>
+#endif
+
 #include "base/scoped_ptr.h"
+#include "net/base/address_list.h"
 #include "net/base/mock_host_resolver.h"
 #include "net/base/net_errors.h"
 #include "net/base/net_util.h"
@@ -12,6 +21,67 @@
 namespace net {
 namespace {
 
+// This is a HostResolver that synchronously resolves all hosts to the
+// following address list of length 3:
+//     192.168.1.1
+//     172.22.34.1
+//     200.100.1.2
+class MockHostResolverWithMultipleResults : public HostResolver {
+ public:
+  // HostResolver methods:
+  virtual int Resolve(const RequestInfo& info,
+                      AddressList* addresses,
+                      CompletionCallback* callback,
+                      RequestHandle* out_req,
+                      LoadLog* load_log) {
+    // Build up the result list (in reverse).
+    AddressList temp_list = ResolveIPLiteral("200.100.1.2");
+    temp_list = PrependAddressToList("172.22.34.1", temp_list);
+    temp_list = PrependAddressToList("192.168.1.1", temp_list);
+    *addresses = temp_list;
+    return OK;
+  }
+  virtual void CancelRequest(RequestHandle req) {}
+  virtual void AddObserver(Observer* observer) {}
+  virtual void RemoveObserver(Observer* observer) {}
+  virtual HostCache* GetHostCache() { return NULL; }
+  virtual void Shutdown() {}
+
+ private:
+  // Resolves an IP literal to an address list.
+  AddressList ResolveIPLiteral(const char* ip_literal) {
+    AddressList result;
+    int rv = SystemHostResolverProc(ip_literal,
+                                    ADDRESS_FAMILY_UNSPECIFIED,
+                                    &result);
+    EXPECT_EQ(OK, rv);
+    EXPECT_EQ(NULL, result.head()->ai_next);
+    return result;
+  }
+
+  // Builds an AddressList that is |ip_literal| + |address_list|.
+  // |orig_list| must not be empty.
+  AddressList PrependAddressToList(const char* ip_literal,
+                                   const AddressList& orig_list) {
+    // Build an addrinfo for |ip_literal|.
+    AddressList result = ResolveIPLiteral(ip_literal);
+
+    struct addrinfo* result_head = const_cast<struct addrinfo*>(result.head());
+
+    // Temporarily append |orig_list| to |result|.
+    result_head->ai_next = const_cast<struct addrinfo*>(orig_list.head());
+
+    // Make a copy of the concatenated list.
+    AddressList concatenated;
+    concatenated.Copy(result.head());
+
+    // Restore |result| (so it is freed properly).
+    result_head->ai_next = NULL;
+
+    return concatenated;
+  }
+};
+
 TEST(ProxyResolverJSBindingsTest, DnsResolve) {
   scoped_refptr<MockHostResolver> host_resolver(new MockHostResolver);
 
@@ -21,6 +91,7 @@ TEST(ProxyResolverJSBindingsTest, DnsResolve) {
 
   // Empty string is not considered a valid host (even though on some systems
   // requesting this will resolve to localhost).
+  host_resolver->rules()->AddSimulatedFailure("");
   EXPECT_EQ("", bindings->DnsResolve(""));
 
   // Should call through to the HostResolver.
@@ -48,10 +119,19 @@ TEST(ProxyResolverJSBindingsTest, MyIpAddress) {
   EXPECT_EQ("127.0.0.1", my_ip_address);
 }
 
-// Tests that myIpAddress() and dnsResolve() pass the flag
-// ADDRESS_FAMILY_IPV4 to the host resolver, as we don't want them
-// to return IPv6 results.
-TEST(ProxyResolverJSBindingsTest, DontUseIPv6) {
+// Tests that the regular PAC functions restrict results to IPv4,
+// but that the Microsoft extensions to PAC do not. We test this
+// by seeing whether ADDRESS_FAMILY_IPV4 or ADDRESS_FAMILY_UNSPECIFIED
+// was passed into to the host resolver.
+//
+//   Restricted to IPv4 address family:
+//     myIpAddress()
+//     dnsResolve()
+//
+//   Unrestricted address family:
+//     myIpAddressEx()
+//     dnsResolveEx()
+TEST(ProxyResolverJSBindingsTest, RestrictAddressFamily) {
   scoped_refptr<MockHostResolver> host_resolver(new MockHostResolver);
 
   // Get a hold of a DefaultJSBindings* (it is a hidden impl class).
@@ -67,7 +147,9 @@ TEST(ProxyResolverJSBindingsTest, DontUseIPv6) {
   host_resolver->rules()->AddRuleForAddressFamily(
       "*", ADDRESS_FAMILY_IPV4, "192.168.1.2");
   host_resolver->rules()->AddRuleForAddressFamily(
-      "*", ADDRESS_FAMILY_UNSPECIFIED, "192.168.2.1");
+      "foo", ADDRESS_FAMILY_UNSPECIFIED, "192.168.2.1");
+  host_resolver->rules()->AddRuleForAddressFamily(
+      "*", ADDRESS_FAMILY_UNSPECIFIED, "192.168.2.2");
 
   // Verify that our mock setups works as expected, and we get different results
   // depending if the address family was IPV4_ONLY or not.
@@ -81,9 +163,31 @@ TEST(ProxyResolverJSBindingsTest, DontUseIPv6) {
   EXPECT_EQ("192.168.1.1", NetAddressToString(address_list.head()));
 
   // Now the actual test.
-  EXPECT_EQ("192.168.1.2", bindings->MyIpAddress());
-  EXPECT_EQ("192.168.1.1", bindings->DnsResolve("foo"));
-  EXPECT_EQ("192.168.1.2", bindings->DnsResolve("foo2"));
+  EXPECT_EQ("192.168.1.2", bindings->MyIpAddress());       // IPv4 restricted.
+  EXPECT_EQ("192.168.1.1", bindings->DnsResolve("foo"));   // IPv4 restricted.
+  EXPECT_EQ("192.168.1.2", bindings->DnsResolve("foo2"));  // IPv4 restricted.
+
+  EXPECT_EQ("192.168.2.2", bindings->MyIpAddressEx());       // Unrestricted.
+  EXPECT_EQ("192.168.2.1", bindings->DnsResolveEx("foo"));   // Unrestricted.
+  EXPECT_EQ("192.168.2.2", bindings->DnsResolveEx("foo2"));  // Unrestricted.
+}
+
+// Test that myIpAddressEx() and dnsResolveEx() both return a semi-colon
+// separated list of addresses (as opposed to the non-Ex versions which
+// just return the first result).
+TEST(ProxyResolverJSBindingsTest, ExFunctionsReturnList) {
+  scoped_refptr<HostResolver> host_resolver(
+      new MockHostResolverWithMultipleResults);
+
+  // Get a hold of a DefaultJSBindings* (it is a hidden impl class).
+  scoped_ptr<ProxyResolverJSBindings> bindings(
+      ProxyResolverJSBindings::CreateDefault(host_resolver, NULL));
+
+  EXPECT_EQ("192.168.1.1;172.22.34.1;200.100.1.2",
+            bindings->MyIpAddressEx());
+
+  EXPECT_EQ("192.168.1.1;172.22.34.1;200.100.1.2",
+            bindings->DnsResolveEx("FOO"));
 }
 
 }  // namespace
diff --git a/net/proxy/proxy_resolver_script.h b/net/proxy/proxy_resolver_script.h
index be592e4..a872cba 100644
--- a/net/proxy/proxy_resolver_script.h
+++ b/net/proxy/proxy_resolver_script.h
@@ -263,6 +263,14 @@
   "        date.setSeconds(date.getUTCSeconds());\n" \
   "    }\n" \
   "    return ((date1 <= date) && (date <= date2));\n" \
-  "}\n" \
+  "}\n"
+
+// This is a Microsoft extension to PAC for IPv6, see:
+// http://blogs.msdn.com/wndp/articles/IPV6_PAC_Extensions_v0_9.aspx
+#define PROXY_RESOLVER_SCRIPT_EX \
+  "function isResolvableEx(host) {\n" \
+  "    var ipList = dnsResolveEx(host);\n" \
+  "    return (ipList != '');\n" \
+  "}\n"
 
 #endif  // NET_PROXY_PROXY_RESOLVER_SCRIPT_H_
diff --git a/net/proxy/proxy_resolver_v8.cc b/net/proxy/proxy_resolver_v8.cc
index 7fd00bd..4db6bc3 100644
--- a/net/proxy/proxy_resolver_v8.cc
+++ b/net/proxy/proxy_resolver_v8.cc
@@ -14,6 +14,51 @@
 #include "net/proxy/proxy_resolver_script.h"
 #include "v8/include/v8.h"
 
+// Notes on the javascript environment:
+//
+// For the majority of the PAC utility functions, we use the same code
+// as Firefox. See the javascript library that proxy_resolver_scipt.h
+// pulls in.
+//
+// In addition, we implement a subset of Microsoft's extensions to PAC.
+// TODO(eroman): Implement the rest.
+//
+//   - myIpAddressEx()
+//   - dnsResolveEx()
+//   - isResolvableEx()
+//
+// It is worth noting that the original PAC specification does not describe
+// the return values on failure. Consequently, there are compatibility
+// differences between browsers on what to return on failure, which are
+// illustrated below:
+//
+// ----------------+-------------+-------------------+--------------
+//                 | Firefox3    | InternetExplorer8 |  --> Us <---
+// ----------------+-------------+-------------------+--------------
+// myIpAddress()   | "127.0.0.1" |  ???              |  "127.0.0.1"
+// dnsResolve()    | null        |  false            |  null
+// myIpAddressEx() | N/A         |  ""               |  ""
+// dnsResolveEx()  | N/A         |  ""               |  ""
+// ----------------+-------------+-------------------+--------------
+//
+// TODO(eroman): The cell above reading ??? means I didn't test it.
+//
+// Another difference is in how dnsResolve() and myIpAddress() are
+// implemented -- whether they should restrict to IPv4 results, or
+// include both IPv4 and IPv6. The following table illustrates the
+// differences:
+//
+// -----------------+-------------+-------------------+--------------
+//                  | Firefox3    | InternetExplorer8 |  --> Us <---
+// -----------------+-------------+-------------------+--------------
+// myIpAddress()    | IPv4/IPv6   |  IPv4             |  IPv4
+// dnsResolve()     | IPv4/IPv6   |  IPv4             |  IPv4
+// isResolvable()   | IPv4/IPv6   |  IPv4             |  IPv4
+// myIpAddressEx()  | N/A         |  IPv4/IPv6        |  IPv4/IPv6
+// dnsResolveEx()   | N/A         |  IPv4/IPv6        |  IPv4/IPv6
+// isResolvableEx() | N/A         |  IPv4/IPv6        |  IPv4/IPv6
+// -----------------+-------------+-------------------+--------------
+
 namespace net {
 
 namespace {
@@ -128,13 +173,28 @@ class ProxyResolverV8::Context {
     global_template->Set(v8::String::New("dnsResolve"),
         dns_resolve_template);
 
+    // Microsoft's PAC extensions (incomplete):
+
+    v8::Local<v8::FunctionTemplate> dns_resolve_ex_template =
+        v8::FunctionTemplate::New(&DnsResolveExCallback, v8_this_);
+    global_template->Set(v8::String::New("dnsResolveEx"),
+                         dns_resolve_ex_template);
+
+    v8::Local<v8::FunctionTemplate> my_ip_address_ex_template =
+        v8::FunctionTemplate::New(&MyIpAddressExCallback, v8_this_);
+    global_template->Set(v8::String::New("myIpAddressEx"),
+                         my_ip_address_ex_template);
+
     v8_context_ = v8::Context::New(NULL, global_template);
 
     v8::Context::Scope ctx(v8_context_);
 
     // Add the PAC utility functions to the environment.
     // (This script should never fail, as it is a string literal!)
-    int rv = RunScript(PROXY_RESOLVER_SCRIPT, kPacUtilityResourceName);
+    // Note that the two string literals are concatenated.
+    int rv = RunScript(PROXY_RESOLVER_SCRIPT
+                       PROXY_RESOLVER_SCRIPT_EX,
+                       kPacUtilityResourceName);
     if (rv != OK) {
       NOTREACHED();
       return rv;
@@ -248,6 +308,25 @@ class ProxyResolverV8::Context {
     return StdStringToV8String(result);
   }
 
+  // V8 callback for when "myIpAddressEx()" is invoked by the PAC script.
+  static v8::Handle<v8::Value> MyIpAddressExCallback(
+      const v8::Arguments& args) {
+    Context* context =
+        static_cast<Context*>(v8::External::Cast(*args.Data())->Value());
+
+    LoadLog::BeginEvent(context->current_request_load_log_,
+                        LoadLog::TYPE_PROXY_RESOLVER_V8_MY_IP_ADDRESS_EX);
+
+    // We shouldn't be called with any arguments, but will not complain if
+    // we are.
+    std::string result = context->js_bindings_->MyIpAddressEx();
+
+    LoadLog::EndEvent(context->current_request_load_log_,
+                      LoadLog::TYPE_PROXY_RESOLVER_V8_MY_IP_ADDRESS_EX);
+
+    return StdStringToV8String(result);
+  }
+
   // V8 callback for when "dnsResolve()" is invoked by the PAC script.
   static v8::Handle<v8::Value> DnsResolveCallback(const v8::Arguments& args) {
     Context* context =
@@ -270,10 +349,35 @@ class ProxyResolverV8::Context {
     LoadLog::EndEvent(context->current_request_load_log_,
                       LoadLog::TYPE_PROXY_RESOLVER_V8_DNS_RESOLVE);
 
-    // DoDnsResolve() returns empty string on failure.
+    // DnsResolve() returns empty string on failure.
     return result.empty() ? v8::Null() : StdStringToV8String(result);
   }
 
+  // V8 callback for when "dnsResolveEx()" is invoked by the PAC script.
+  static v8::Handle<v8::Value> DnsResolveExCallback(const v8::Arguments& args) {
+    Context* context =
+        static_cast<Context*>(v8::External::Cast(*args.Data())->Value());
+
+    // We need at least one argument.
+    std::string host;
+    if (args.Length() == 0) {
+      host = "undefined";
+    } else {
+      if (!V8ObjectToString(args[0], &host))
+        return v8::Undefined();
+    }
+
+    LoadLog::BeginEvent(context->current_request_load_log_,
+                        LoadLog::TYPE_PROXY_RESOLVER_V8_DNS_RESOLVE_EX);
+
+    std::string result = context->js_bindings_->DnsResolveEx(host);
+
+    LoadLog::EndEvent(context->current_request_load_log_,
+                      LoadLog::TYPE_PROXY_RESOLVER_V8_DNS_RESOLVE_EX);
+
+    return StdStringToV8String(result);
+  }
+
   ProxyResolverJSBindings* js_bindings_;
   LoadLog* current_request_load_log_;
   v8::Persistent<v8::External> v8_this_;
diff --git a/net/proxy/proxy_resolver_v8_unittest.cc b/net/proxy/proxy_resolver_v8_unittest.cc
index c172093..550426a 100644
--- a/net/proxy/proxy_resolver_v8_unittest.cc
+++ b/net/proxy/proxy_resolver_v8_unittest.cc
@@ -21,7 +21,7 @@ namespace {
 // list, for later verification.
 class MockJSBindings : public ProxyResolverJSBindings {
  public:
-  MockJSBindings() : my_ip_address_count(0) {}
+  MockJSBindings() : my_ip_address_count(0), my_ip_address_ex_count(0) {}
 
   virtual void Alert(const std::string& message) {
     LOG(INFO) << "PAC-alert: " << message;  // Helpful when debugging.
@@ -33,11 +33,21 @@ class MockJSBindings : public ProxyResolverJSBindings {
     return my_ip_address_result;
   }
 
+  virtual std::string MyIpAddressEx() {
+    my_ip_address_ex_count++;
+    return my_ip_address_ex_result;
+  }
+
   virtual std::string DnsResolve(const std::string& host) {
     dns_resolves.push_back(host);
     return dns_resolve_result;
   }
 
+  virtual std::string DnsResolveEx(const std::string& host) {
+    dns_resolves_ex.push_back(host);
+    return dns_resolve_ex_result;
+  }
+
   virtual void OnError(int line_number, const std::string& message) {
     // Helpful when debugging.
     LOG(INFO) << "PAC-error: [" << line_number << "] " << message;
@@ -48,14 +58,18 @@ class MockJSBindings : public ProxyResolverJSBindings {
 
   // Mock values to return.
   std::string my_ip_address_result;
+  std::string my_ip_address_ex_result;
   std::string dns_resolve_result;
+  std::string dns_resolve_ex_result;
 
   // Inputs we got called with.
   std::vector<std::string> alerts;
   std::vector<std::string> errors;
   std::vector<int> errors_line_number;
   std::vector<std::string> dns_resolves;
+  std::vector<std::string> dns_resolves_ex;
   int my_ip_address_count;
+  int my_ip_address_ex_count;
 };
 
 // This is the same as ProxyResolverV8, but it uses mock bindings in place of
@@ -391,6 +405,14 @@ TEST(ProxyResolverV8Test, V8Bindings) {
 
   // MyIpAddress was called two times.
   EXPECT_EQ(2, bindings->my_ip_address_count);
+
+  // MyIpAddressEx was called once.
+  EXPECT_EQ(1, bindings->my_ip_address_ex_count);
+
+  // DnsResolveEx was called 2 times.
+  ASSERT_EQ(2U, bindings->dns_resolves_ex.size());
+  EXPECT_EQ("is_resolvable", bindings->dns_resolves_ex[0]);
+  EXPECT_EQ("foobar", bindings->dns_resolves_ex[1]);
 }
 
 // Test that calls to the myIpAddress() and dnsResolve() bindings get
@@ -464,5 +486,22 @@ TEST(ProxyResolverV8Test, EndsWithStatementNoNewline) {
   EXPECT_EQ("success:3", proxy_info.proxy_server().ToURI());
 }
 
+// Test the return values from myIpAddress(), myIpAddressEx(), dnsResolve(),
+// dnsResolveEx(), isResolvable(), isResolvableEx(), when the the binding
+// returns empty string (failure). This simulates the return values from
+// those functions when the underlying DNS resolution fails.
+TEST(ProxyResolverV8Test, DNSResolutionFailure) {
+  ProxyResolverV8WithMockBindings resolver;
+  int result = resolver.SetPacScriptFromDisk("dns_fail.js");
+  EXPECT_EQ(OK, result);
+
+  ProxyInfo proxy_info;
+  result = resolver.GetProxyForURL(kQueryUrl, &proxy_info, NULL, NULL, NULL);
+
+  EXPECT_EQ(OK, result);
+  EXPECT_FALSE(proxy_info.is_direct());
+  EXPECT_EQ("success:80", proxy_info.proxy_server().ToURI());
+}
+
 }  // namespace
 }  // namespace net