Introduce ui.dll / libui.so for the component build.

ui/base/view_prop.h

Index: ui/base/view_prop.h
===================================================================
--- ui/base/view_prop.h	(revision 92815)
+++ ui/base/view_prop.h	(working copy)
@@ -9,6 +9,7 @@
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "ui/gfx/native_widget_types.h"
+#include "ui/ui_api.h"
 
 namespace ui {
 
@@ -16,7 +17,7 @@
 // designed as a replacement for the Win32's SetProp, but does not make use of
 // window manager memory. ViewProp shares similar semantics as SetProp, the
 // value for a particular view/key pair comes from the last ViewProp created.
-class ViewProp {
+class UI_API ViewProp {
  public:
   // Associates data with a view/key pair. If a ViewProp has already been
   // created for the specified pair |data| replaces the current value.