Makes ash/wm/common a library

ash/wm/common/ash_wm_common_export.h

Index: ash/wm/common/ash_wm_common_export.h
diff --git a/ash/wm/common/ash_wm_common_export.h b/ash/wm/common/ash_wm_common_export.h
new file mode 100644
index 0000000000000000000000000000000000000000..a6263504bf4e5c362a7f5c287beb0920a62eb6c3
--- /dev/null
+++ b/ash/wm/common/ash_wm_common_export.h
@@ -0,0 +1,32 @@
+// Copyright 2016 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.
+
+#ifndef ASH_WM_COMMON_ASH_WM_COMMON_EXPORT_H_
+#define ASH_WM_COMMON_ASH_WM_COMMON_EXPORT_H_
+
+// Defines ASH_WM_COMMON_EXPORT so that functionality implemented by the Ash
+// module can be exported to consumers.
+
+#if defined(COMPONENT_BUILD)
+#if defined(WIN32)
+
+#if defined(ASH_WM_COMMON_IMPLEMENTATION)
+#define ASH_WM_COMMON_EXPORT __declspec(dllexport)
+#else
+#define ASH_WM_COMMON_EXPORT __declspec(dllimport)
+#endif  // defined(ASH_WM_COMMON_IMPLEMENTATION)
+
+#else  // defined(WIN32)
+#if defined(ASH_WM_COMMON_IMPLEMENTATION)
+#define ASH_WM_COMMON_EXPORT __attribute__((visibility("default")))
+#else
+#define ASH_WM_COMMON_EXPORT
+#endif
+#endif
+
+#else  // defined(COMPONENT_BUILD)
+#define ASH_WM_COMMON_EXPORT
+#endif
+
+#endif  // ASH_WM_COMMON_ASH_WM_COMMON_EXPORT_H_