Add Android support in DnsConfigServicePosix.

Add support for Android in DnsConfigServicePosix by:
1. Adding ReadDnsConfig that reads the net.dns[12] system properties.
2. Adding ConfigWatcher that triggers on network change events.
3. Pointing HostsWatcher at /system/etc/hosts.

BUG=149752,334794

Review URL: https://codereview.chromium.org/138623003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246101 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 38 insertions, 1 deletions

diff --git a/net/android/network_change_notifier_android.cc b/net/android/network_change_notifier_android.cc
index d4e1a5c..e0f5244 100644
--- a/net/android/network_change_notifier_android.cc
+++ b/net/android/network_change_notifier_android.cc
@@ -59,8 +59,39 @@
 
 #include "net/android/network_change_notifier_android.h"
 
+#include "base/threading/thread.h"
+#include "net/dns/dns_config_service.h"
+
 namespace net {
 
+// Thread on which we can run DnsConfigService, which requires a TYPE_IO
+// message loop to monitor /system/etc/hosts.
+class NetworkChangeNotifierAndroid::DnsConfigServiceThread
+    : public base::Thread {
+ public:
+  DnsConfigServiceThread() : base::Thread("DnsConfigService") {}
+
+  virtual ~DnsConfigServiceThread() {
+    Stop();
+  }
+
+  virtual void Init() OVERRIDE {
+    dns_config_service_ = DnsConfigService::CreateSystemService();
+    dns_config_service_->WatchConfig(
+        base::Bind(&NetworkChangeNotifier::SetDnsConfig));
+  }
+
+  virtual void CleanUp() OVERRIDE {
+    dns_config_service_.reset();
+  }
+
+ private:
+  scoped_ptr<DnsConfigService> dns_config_service_;
+
+  DISALLOW_COPY_AND_ASSIGN(DnsConfigServiceThread);
+};
+
+
 NetworkChangeNotifierAndroid::~NetworkChangeNotifierAndroid() {
   delegate_->RemoveObserver(this);
 }
@@ -83,8 +114,11 @@ bool NetworkChangeNotifierAndroid::Register(JNIEnv* env) {
 NetworkChangeNotifierAndroid::NetworkChangeNotifierAndroid(
     NetworkChangeNotifierDelegateAndroid* delegate)
     : NetworkChangeNotifier(NetworkChangeCalculatorParamsAndroid()),
-      delegate_(delegate) {
+      delegate_(delegate),
+      dns_config_service_thread_(new DnsConfigServiceThread()) {
   delegate_->AddObserver(this);
+  dns_config_service_thread_->StartWithOptions(
+      base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
 }
 
 // static
diff --git a/net/android/network_change_notifier_android.h b/net/android/network_change_notifier_android.h
index f167cfc..e82b852 100644
--- a/net/android/network_change_notifier_android.h
+++ b/net/android/network_change_notifier_android.h
@@ -56,12 +56,15 @@ class NET_EXPORT_PRIVATE NetworkChangeNotifierAndroid
   friend class NetworkChangeNotifierAndroidTest;
   friend class NetworkChangeNotifierFactoryAndroid;
 
+  class DnsConfigServiceThread;
+
   explicit NetworkChangeNotifierAndroid(
       NetworkChangeNotifierDelegateAndroid* delegate);
 
   static NetworkChangeCalculatorParams NetworkChangeCalculatorParamsAndroid();
 
   NetworkChangeNotifierDelegateAndroid* const delegate_;
+  scoped_ptr<DnsConfigServiceThread> dns_config_service_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifierAndroid);
 };