Cleanup: Remove ViewProp from aura build

ui/ui.gyp

Index: ui/ui.gyp
diff --git a/ui/ui.gyp b/ui/ui.gyp
index 7fbe5d06b5dfc0dfa18df7f1f804fa78264e92b3..43763f75b4ddc7be9dd1b3dde6c325d729568e65 100644
--- a/ui/ui.gyp
+++ b/ui/ui.gyp
@@ -321,6 +321,8 @@
             ['exclude', 'gfx/native_theme_chromeos.cc'],
             ['exclude', 'gfx/native_theme_chromeos.h'],
             ['exclude', 'gfx/screen_win.cc'],
+            ['exclude', 'base/view_prop.cc'],
+            ['exclude', 'base/view_prop.h'],
             ['exclude', 'base/win/mouse_wheel_util.cc'],
             ['exclude', 'base/win/mouse_wheel_util.h'],
             ['exclude', 'base/x/active_window_watcher_x.cc'],
@@ -406,8 +408,6 @@
             ['include', 'base/dragdrop/os_exchange_data_provider_gtk.h'],
             ['include', 'base/keycodes/keyboard_code_conversion_x.cc'],
             ['include', 'base/keycodes/keyboard_code_conversion_x.h'],
-            ['include', 'base/view_prop.cc'],
-            ['include', 'base/view_prop.h'],
             ['include', 'gfx/gtk_util.cc'],
             ['include', 'gfx/gtk_util.h'],
             ['include', 'gfx/path_gtk.cc'],
@@ -469,6 +469,8 @@
             'base/dragdrop/drop_target.cc',
             'base/dragdrop/drop_target.h',
             'base/dragdrop/os_exchange_data.cc',
+            'base/view_prop.cc',
+            'base/view_prop.h',
             'gfx/native_theme_win.cc',
             'gfx/native_theme_win.h',
           ],
@@ -529,8 +531,6 @@
         }],
         ['toolkit_views==0', {
           'sources!': [
-            'base/view_prop.cc',
-            'base/view_prop.h',
             'gfx/render_text.cc',
             'gfx/render_text.h',
             'gfx/render_text_linux.cc',