Implement standalone event tracing in AppRTCDemo.

webrtc/examples/androidapp/src/org/appspot/apprtc/SettingsActivity.java

Index: webrtc/examples/androidapp/src/org/appspot/apprtc/SettingsActivity.java
diff --git a/webrtc/examples/androidapp/src/org/appspot/apprtc/SettingsActivity.java b/webrtc/examples/androidapp/src/org/appspot/apprtc/SettingsActivity.java
index f3cc770d18a5c7a3eefa11d462900141255d36ec..b0739bc2df570a6b3d958f2179c1b9ab7b9c6cc9 100644
--- a/webrtc/examples/androidapp/src/org/appspot/apprtc/SettingsActivity.java
+++ b/webrtc/examples/androidapp/src/org/appspot/apprtc/SettingsActivity.java
@@ -39,6 +39,7 @@ public class SettingsActivity extends Activity
 
   private String keyPrefRoomServerUrl;
   private String keyPrefDisplayHud;
+  private String keyPrefTracing;
 
   @Override
   protected void onCreate(Bundle savedInstanceState) {
@@ -60,6 +61,7 @@ public class SettingsActivity extends Activity
 
     keyPrefRoomServerUrl = getString(R.string.pref_room_server_url_key);
     keyPrefDisplayHud = getString(R.string.pref_displayhud_key);
+    keyPrefTracing = getString(R.string.pref_tracing_key);
 
     // Display the fragment as the main content.
     settingsFragment = new SettingsFragment();
@@ -94,6 +96,7 @@ public class SettingsActivity extends Activity
 
     updateSummary(sharedPreferences, keyPrefRoomServerUrl);
     updateSummaryB(sharedPreferences, keyPrefDisplayHud);
+    updateSummaryB(sharedPreferences, keyPrefTracing);
   }
 
   @Override
@@ -123,7 +126,8 @@ public class SettingsActivity extends Activity
         || key.equals(keyprefHwCodec)
         || key.equals(keyprefNoAudioProcessing)
         || key.equals(keyprefOpenSLES)
-        || key.equals(keyPrefDisplayHud)) {
+        || key.equals(keyPrefDisplayHud)
+        || key.equals(keyPrefTracing)) {
       updateSummaryB(sharedPreferences, key);
     }
     if (key.equals(keyprefStartVideoBitrateType)) {