First cut at UI for saving net_internals data into a file for mobile (Android and Ios).

chrome/browser/resources/net_internals/browser_bridge.js

Index: chrome/browser/resources/net_internals/browser_bridge.js
===================================================================
--- chrome/browser/resources/net_internals/browser_bridge.js	(revision 171385)
+++ chrome/browser/resources/net_internals/browser_bridge.js	(working copy)
@@ -200,6 +200,18 @@
       this.send('getHistoricNetworkStats');
     },
 
+    sendStartNetLog: function() {
+      this.send('startNetLog');
+    },
+
+    sendStopNetLog: function() {
+      this.send('stopNetLog');
+    },
+
+    sendSendNetLog: function() {
+      this.send('sendNetLog');
+    },
+
     sendCloseIdleSockets: function() {
       this.send('closeIdleSockets');
     },