Adds support for the DHCP portion of the WPAD (proxy auto-discovery) protocol.

This is Windows-only for now, and is disabled by default.  Start
Chrome with the flag --enable-dhcp-wpad to enable the feature.  See
discussion in comment on DhcpProxyScriptFetcherFactory for why this
needs to be done in a per-platform way rather than cross-platform.
The code is factored so that adding other platform implementations
will be straight forward.

Most of the implementation is stand-alone and extends the
ScriptProxyFetcher class hierarchy (and makes its interface slightly
more generic).  The integration point into existing code is in
InitProxyResolver, which previously handled fallback from DNS
auto-detect to custom PAC URL and now does fallback from DHCP to DNS
to custom PAC URL.

BUG=18575
TEST=net_unittests has good coverage for the new and changed code, but
manual tests on a network with a PAC URL configured in DHCP are also
needed.

Original commit r85646.
Reverted (test failures on some release bots) r85648.
Will reland with fix.

Review URL: http://codereview.chromium.org/6831025

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@85661 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 29 insertions, 7 deletions

diff --git a/chrome/browser/net/connection_tester.cc b/chrome/browser/net/connection_tester.cc
index 84d45d9..3aa578e 100644
--- a/chrome/browser/net/connection_tester.cc
+++ b/chrome/browser/net/connection_tester.cc
@@ -26,6 +26,7 @@
 #include "net/http/http_auth_handler_factory.h"
 #include "net/http/http_cache.h"
 #include "net/http/http_network_session.h"
+#include "net/proxy/dhcp_proxy_script_fetcher_factory.h"
 #include "net/proxy/proxy_config_service_fixed.h"
 #include "net/proxy/proxy_script_fetcher_impl.h"
 #include "net/proxy/proxy_service.h"
@@ -182,10 +183,17 @@ class ExperimentURLRequestContext : public net::URLRequestContext {
       return net::ERR_NOT_IMPLEMENTED;
     }
 
+    net::DhcpProxyScriptFetcherFactory dhcp_factory;
+    if (CommandLine::ForCurrentProcess()->HasSwitch(
+        switches::kEnableDhcpWpad)) {
+      dhcp_factory.set_enabled(true);
+    }
+
     proxy_service->reset(net::ProxyService::CreateUsingV8ProxyResolver(
         config_service.release(),
         0u,
         new net::ProxyScriptFetcherImpl(proxy_request_context_),
+        dhcp_factory.Create(proxy_request_context_),
         host_resolver(),
         NULL,
         NULL));
diff --git a/chrome/browser/net/proxy_service_factory.cc b/chrome/browser/net/proxy_service_factory.cc
index ba1cb9a..cf97923 100644
--- a/chrome/browser/net/proxy_service_factory.cc
+++ b/chrome/browser/net/proxy_service_factory.cc
@@ -12,6 +12,7 @@
 #include "chrome/common/chrome_switches.h"
 #include "content/browser/browser_thread.h"
 #include "net/base/net_log.h"
+#include "net/proxy/dhcp_proxy_script_fetcher_factory.h"
 #include "net/proxy/proxy_config_service.h"
 #include "net/proxy/proxy_script_fetcher_impl.h"
 #include "net/proxy/proxy_service.h"
@@ -84,10 +85,16 @@ net::ProxyService* ProxyServiceFactory::CreateProxyService(
 
   net::ProxyService* proxy_service;
   if (use_v8) {
+    net::DhcpProxyScriptFetcherFactory dhcp_factory;
+    if (command_line.HasSwitch(switches::kEnableDhcpWpad)) {
+      dhcp_factory.set_enabled(true);
+    }
+
     proxy_service = net::ProxyService::CreateUsingV8ProxyResolver(
         proxy_config_service,
         num_pac_threads,
         new net::ProxyScriptFetcherImpl(context),
+        dhcp_factory.Create(context),
         context->host_resolver(),
         net_log,
         context->network_delegate());
diff --git a/chrome/chrome_dll.gypi b/chrome/chrome_dll.gypi
index a861546..7d89653 100644
--- a/chrome/chrome_dll.gypi
+++ b/chrome/chrome_dll.gypi
@@ -23,19 +23,20 @@
               'VCLinkerTool': {
                 'BaseAddress': '0x01c30000',
                 'DelayLoadDLLs': [
+                  'comdlg32.dll',
                   'crypt32.dll',
                   'cryptui.dll',
-                  'winhttp.dll',
-                  'wininet.dll',
-                  'wsock32.dll',
-                  'ws2_32.dll',
-                  'winspool.drv',
-                  'comdlg32.dll',
+                  'dhcpcsvc.dll',
                   'imagehlp.dll',
-                  'urlmon.dll',
                   'imm32.dll',
                   'iphlpapi.dll',
                   'setupapi.dll',
+                  'urlmon.dll',
+                  'winhttp.dll',
+                  'wininet.dll',
+                  'winspool.drv',
+                  'ws2_32.dll',
+                  'wsock32.dll',
                 ],
                 # Set /SUBSYSTEM:WINDOWS for chrome.dll (for consistency).
                 'SubSystem': '2',
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 1f58615..4afe3a8 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -402,6 +402,11 @@ const char kEnableConnectBackupJobs[]       = "enable-connect-backup-jobs";
 // Enables web developers to create apps for Chrome without using crx packages.
 const char kEnableCrxlessWebApps[]          = "enable-crxless-web-apps";
 
+// Enables retrieval of PAC URLs from DHCP as per the WPAD standard. Note
+// that this feature is not supported on all platforms, and using the flag
+// is a no-op on such platforms.
+const char kEnableDhcpWpad[]                = "enable-dhcp-wpad";
+
 // Enable DNS side checking of certificates. Still experimental, should only
 // be used by developers at the current time.
 const char kEnableDNSCertProvenanceChecking[] =
diff --git a/chrome/common/chrome_switches.h b/chrome/common/chrome_switches.h
index c4876d7..aa4cb99 100644
--- a/chrome/common/chrome_switches.h
+++ b/chrome/common/chrome_switches.h
@@ -122,6 +122,7 @@ extern const char kEnableCompactNavigation[];
 extern const char kEnableCompositeToTexture[];
 extern const char kEnableConnectBackupJobs[];
 extern const char kEnableCrxlessWebApps[];
+extern const char kEnableDhcpWpad[];
 extern const char kEnableDNSCertProvenanceChecking[];
 extern const char kEnableDNSSECCerts[];
 extern const char kEnableExperimentalAppManifests[];