Makes ui::GetSupportedScaleFactors available on platforms other than Mac

ui/base/layout.h

Index: ui/base/layout.h
diff --git a/ui/base/layout.h b/ui/base/layout.h
index 447dfacc1cada26bfdb75d26951aa1c0390c56e5..35aa5675c9bd5586c4cc125c185133e0c31d0d6e 100644
--- a/ui/base/layout.h
+++ b/ui/base/layout.h
@@ -53,13 +53,13 @@ UI_EXPORT ScaleFactor GetScaleFactorFromScale(float scale);
 // Returns the ScaleFactor used by |view|.
 UI_EXPORT ScaleFactor GetScaleFactorForNativeView(gfx::NativeView view);
 
-#if defined(OS_MACOSX)
-
 // Returns a vector with the scale factors which are supported by this
 // platform.
-// Only required on Mac so far.
 UI_EXPORT std::vector<ScaleFactor> GetSupportedScaleFactors();
 
+// Returns true if |scale_factor| is supported by this platform.
+UI_EXPORT bool IsScaleFactorSupported(ScaleFactor scale_factor);
+
 namespace test {
 
 UI_EXPORT void SetSupportedScaleFactors(
@@ -67,8 +67,6 @@ UI_EXPORT void SetSupportedScaleFactors(
 
 }  // namespace test
 
-#endif
-
 }  // namespace ui
 
 #endif  // UI_BASE_LAYOUT_H_