events: Create a separate platforms target.

ui/events/platform/events_platform.gyp

Index: ui/events/platform/events_platform.gyp
diff --git a/ui/events/platform/events_platform.gyp b/ui/events/platform/events_platform.gyp
new file mode 100644
index 0000000000000000000000000000000000000000..d1b3f6bfe3ec9d6ad4ee02967f031a4def2ef0fe
--- /dev/null
+++ b/ui/events/platform/events_platform.gyp
@@ -0,0 +1,36 @@
+# Copyright 2014 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': {
+    'chromium_code': 1,
+  },
+  'targets': [{
+    'target_name': 'events_platform',
+    'type': '<(component)',
+    'dependencies': [
+      '../../../base/base.gyp:base',
+    ],
+    'defines': [
+      'EVENTS_IMPLEMENTATION',
+    ],
+    'sources': [
+      'platform_event_dispatcher.h',
+      'platform_event_observer.h',
+      'platform_event_source.cc',
+      'platform_event_source.h',
+      'platform_event_source_stub.cc',
+      'platform_event_types.h',
+      'scoped_event_dispatcher.cc',
+      'scoped_event_dispatcher.h',
+    ],
+    'conditions': [
+      ['use_x11==1', {
+        'sources!': [
+          'platform_event_source_stub.cc',
+        ],
+      }],
+    ],
+  }],
+}