[Chromoting] (Re-)Enable AppRemoting sample apps by default in all.gyp.

"by default" = whenever we build Chromoting.

This is a re-land of crrev.com/878793003, which failed on
the Official builds.

The build problem has been fixed in crrev.com/886543002.

BUG=

Review URL: https://codereview.chromium.org/875463004

Cr-Commit-Position: refs/heads/master@{#314160}

build/all.gyp

@@ -239,7 +239,7 @@
         }],
         ['remoting==1', {
           'dependencies': [
-            '../remoting/remoting.gyp:*',
+            '../remoting/remoting_all.gyp:remoting_all',
           ],
         }],
         ['use_openssl==0', {

remoting/remoting_all.gyp

+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+{
+  'targets': [
+    {
+      'target_name': 'remoting_all',
+      'type': 'none',
+      'dependencies': [
+        '../remoting/remoting.gyp:*',
+        '../remoting/app_remoting_webapp.gyp:*',
+      ],
+    },  # end of target 'remoting_all'
+  ],  # end of targets
+}