Revert of Changes look for scrollbars on windows

ui/native_theme/native_theme_win.cc

Index: ui/native_theme/native_theme_win.cc
diff --git a/ui/native_theme/native_theme_win.cc b/ui/native_theme/native_theme_win.cc
index bf21dcbd17808e7fb23f1280e119a3139e8c86e4..74b4f14a26163b5e27c5c8b1828c7f4500a674d6 100644
--- a/ui/native_theme/native_theme_win.cc
+++ b/ui/native_theme/native_theme_win.cc
@@ -233,6 +233,7 @@
 
   // The GetThemePartSize call below returns the default size without
   // accounting for user customization (crbug/218291).
+  SIZE size;
   switch (part) {
     case kScrollbarDownArrow:
     case kScrollbarLeftArrow:
@@ -241,18 +242,14 @@
     case kScrollbarHorizontalThumb:
     case kScrollbarVerticalThumb:
     case kScrollbarHorizontalTrack:
-    case kScrollbarVerticalTrack: {
-      int size = gfx::win::GetSystemMetricsInDIP(SM_CXVSCROLL);
-      if (size == 0)
-        size = 17;
-      return gfx::Size(size, size);
-    }
+    case kScrollbarVerticalTrack:
+      size.cx = size.cy = gfx::win::GetSystemMetricsInDIP(SM_CXVSCROLL);
+      return gfx::Size(size.cx, size.cy);
   }
 
   int part_id = GetWindowsPart(part, state, extra);
   int state_id = GetWindowsState(part, state, extra);
 
-  SIZE size;
   HDC hdc = GetDC(NULL);
   HRESULT hr = GetThemePartSize(GetThemeName(part), hdc, part_id, state_id,
                                 NULL, TS_TRUE, &size);