Add plugins::TestPluginPlaceholder class and allow its use in Blink layout tests.

components/plugins.gypi

 # Copyright 2013 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': [
     {
       # GN version: //components/plugins/common
       'target_name': 'plugins_common',
       'type': 'static_library',
@@ skipping 40 matching lines @@
             }],
             ['OS=="android"', {
               'sources': [
                 # Note: sources list duplicated in GN build.
                 'plugins/renderer/mobile_youtube_plugin.cc',
                 'plugins/renderer/mobile_youtube_plugin.h',
               ]
             }],
           ],
         },
+        {
+          # GN version: //components/plugins/renderer

[tommycli, 2015/05/26 20:08:18]

This isn't in the GN file.

+          'target_name': 'test_plugins_renderer',
+          'type': 'static_library',
+          'dependencies': [
+            'plugins_renderer',
+            '../third_party/WebKit/public/blink.gyp:blink',
+
+          ],
+          'include_dirs': [
+            '..',
+          ],
+          'sources': [
+            # Note: sources list duplicated in GN build.
+            'plugins/renderer/test_plugin_placeholder.cc',
+            'plugins/renderer/test_plugin_placeholder.h',
+          ],
+        }
       ],
     }],
   ],
 }