Added functionality to chrome://net-internals/#chromeos page that user

chromeos/dbus/debug_daemon_client.cc

Index: chromeos/dbus/debug_daemon_client.cc
diff --git a/chromeos/dbus/debug_daemon_client.cc b/chromeos/dbus/debug_daemon_client.cc
index bc8e06dc71bb46f8e18cfd5afb05bf0aa8f0cade..1426abd0fdc27eb565ea6fda20613e232b9a92f2 100644
--- a/chromeos/dbus/debug_daemon_client.cc
+++ b/chromeos/dbus/debug_daemon_client.cc
@@ -150,6 +150,20 @@ class DebugDaemonClientImpl : public DebugDaemonClient {
   virtual ~DebugDaemonClientImpl() {}
 
   // DebugDaemonClient override.
+  virtual void SetDebugMode(const std::string& subsystem,
+                            const SetDebugModeCallback& callback) OVERRIDE {
+    dbus::MethodCall method_call(debugd::kDebugdInterface,
+                                 debugd::kSetDebugMode);
+    dbus::MessageWriter writer(&method_call);
+    writer.AppendString(subsystem);
+    debugdaemon_proxy_->CallMethod(
+        &method_call,
+        dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
+        base::Bind(&DebugDaemonClientImpl::OnSetDebugMode,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   callback));
+  }
+
   virtual void StartSystemTracing() OVERRIDE {
     dbus::MethodCall method_call(
         debugd::kDebugdInterface,
@@ -209,6 +223,17 @@ class DebugDaemonClientImpl : public DebugDaemonClient {
   }
 
  private:
+  // Called when a response for SetDebugMode() is received.
+  void OnSetDebugMode(const SetDebugModeCallback& callback,
+                      dbus::Response* response) {
+    if (!response) {
+      LOG(ERROR) << "Failed to change debug mode";
+      callback.Run(false);
+    } else {
+      callback.Run(true);
+    }
+  }
+
   // Called when a response for StartSystemTracing() is received.
   void OnStartSystemTracing(dbus::Response* response) {
     if (!response) {
@@ -244,6 +269,10 @@ class DebugDaemonClientImpl : public DebugDaemonClient {
 // which does nothing.
 class DebugDaemonClientStubImpl : public DebugDaemonClient {
   // DebugDaemonClient overrides.
+  virtual void SetDebugMode(const std::string& subsystem,
+                            const SetDebugModeCallback& callback) OVERRIDE {
+    callback.Run(false);
+  }
   virtual void StartSystemTracing() OVERRIDE {}
   virtual bool RequestStopSystemTracing(const StopSystemTracingCallback&
       callback) OVERRIDE {