Add captive portal API.

This API allows apps other than the system's CaptivePortalLogin
to handle signing in to captive portals.

bug:19416463
Change-Id: I27fce5856b635233e6ff66396d50ccabedd76cf5
diff --git a/packages/CaptivePortalLogin/AndroidManifest.xml b/packages/CaptivePortalLogin/AndroidManifest.xml
index 2ec15be..aea8585 100644
--- a/packages/CaptivePortalLogin/AndroidManifest.xml
+++ b/packages/CaptivePortalLogin/AndroidManifest.xml
@@ -21,6 +21,7 @@
 
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.CONNECTIVITY_INTERNAL" />
 
     <application android:label="@string/app_name" >
         <activity
@@ -28,9 +29,8 @@
             android:label="@string/action_bar_label"
             android:theme="@style/AppTheme" >
             <intent-filter>
-                <action android:name="android.intent.action.ACTION_SEND"/>
+                <action android:name="android.net.conn.CAPTIVE_PORTAL"/>
                 <category android:name="android.intent.category.DEFAULT"/>
-                <data android:mimeType="text/plain"/>
             </intent-filter>
         </activity>
     </application>