Always add 100P scale format in the supported format list.

ui/base/layout.cc

Index: ui/base/layout.cc
diff --git a/ui/base/layout.cc b/ui/base/layout.cc
index 6fef499542c57632fb6afc58a7d821309ce5d193..98df1e1ff187ddc222cc61de33651d8c35943909 100644
--- a/ui/base/layout.cc
+++ b/ui/base/layout.cc
@@ -73,18 +73,18 @@ std::vector<ScaleFactor>& GetSupportedScaleFactorsInternal() {
   static std::vector<ScaleFactor>* supported_scale_factors =
       new std::vector<ScaleFactor>();
   if (supported_scale_factors->empty()) {
-#if !defined(OS_IOS)
-    // On platforms other than iOS, 100P is always a supported scale factor.
+    // 100P is always a supported scale factor.
     supported_scale_factors->push_back(SCALE_FACTOR_100P);
-#endif
 
 #if defined(OS_IOS)
+    // TODO(ios): 100p should not be necessary on iOS retina devices. However
+    // the sync service only supports syncing 100p favicons. Until sync supports
+    // other scales 100p is needed in the list of scale factors to retrieve and
+    // store the favicons in both 100p for sync and 200p for display. cr/160503.
     gfx::Display display = gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
     if (display.device_scale_factor() > 1.0) {
       DCHECK_EQ(2.0, display.device_scale_factor());
       supported_scale_factors->push_back(SCALE_FACTOR_200P);
-    } else {
-      supported_scale_factors->push_back(SCALE_FACTOR_100P);
     }
 #elif defined(OS_MACOSX)
     if (base::mac::IsOSLionOrLater())