Removes NPAPI tests from aura build as they don't make sense. There is

chrome/chrome_tests.gypi

 # Copyright (c) 2011 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.
 {
   'variables' : {
     # Variables for js2gtest rules
     'gypv8sh': '../tools/gypv8sh.py',
     'js2gtest': 'test/base/js2gtest.js',
     'mock_js': 'third_party/mock4js/mock4js.js',
     'test_api_js': 'test/data/webui/test_api.js',
@@ skipping 792 matching lines @@
           ],
         }],
         ['toolkit_views==1', {
           'dependencies': [
             '../views/views.gyp:views',
           ],
         }],
         ['use_aura==1', {
           'sources!': [
             'test/automation/automation_proxy_uitest.cc',
+            'test/ui/npapi_uitest.cc',
           ],
           'dependencies': [
             '../ui/aura/aura.gyp:aura',
           ],
         }],
         ['OS=="mac"', {
           # See the comment in this section of the unit_tests target for an
           # explanation (crbug.com/43791 - libwebcore.a is too large to mmap).
           'dependencies+++': [
             '../third_party/WebKit/Source/WebCore/WebCore.gyp/WebCore.gyp:webcore',
@@ skipping 3444 matching lines @@
               # Use outputs of this action as inputs for the main target build.
               # Seems as a misnomer but makes this happy on Linux (scons).
               'process_outputs_as_sources': 1,
             },
           ],  # 'actions'
         },
       ]
     }],  # 'coverage!=0'
   ],  # 'conditions'
 }