Change name of NativeTheme::instance() to make it clear it's web only.

ui/views/controls/scrollbar/native_scroll_bar_views.cc

Index: ui/views/controls/scrollbar/native_scroll_bar_views.cc
diff --git a/ui/views/controls/scrollbar/native_scroll_bar_views.cc b/ui/views/controls/scrollbar/native_scroll_bar_views.cc
index d69f79f1ee56e44ce091b25d5960ee8d4e1382f2..5b504d4ad764cbad099d4b1b1cd90cf2503618ef 100644
--- a/ui/views/controls/scrollbar/native_scroll_bar_views.cc
+++ b/ui/views/controls/scrollbar/native_scroll_bar_views.cc
@@ -376,8 +376,6 @@ NativeScrollBarWrapper* NativeScrollBarWrapper::CreateWrapper(
 // static
 int NativeScrollBarWrapper::GetHorizontalScrollBarHeight(
     const ui::NativeTheme* theme) {
-  if (!theme)
-    theme = ui::NativeTheme::instance();

[Evan Stade, 2015/11/19 23:29:14]

likewise I think theme is always non-null here

   ui::NativeTheme::ExtraParams button_params;
   button_params.scrollbar_arrow.is_hovering = false;
   gfx::Size button_size = theme->GetPartSize(
@@ -398,8 +396,6 @@ int NativeScrollBarWrapper::GetHorizontalScrollBarHeight(
 // static
 int NativeScrollBarWrapper::GetVerticalScrollBarWidth(
     const ui::NativeTheme* theme) {
-  if (!theme)
-    theme = ui::NativeTheme::instance();
   ui::NativeTheme::ExtraParams button_params;
   button_params.scrollbar_arrow.is_hovering = false;
   gfx::Size button_size = theme->GetPartSize(