Avoid calling the GetSystemMetrics API in the renderer process on Windows to get the scrollbar metr…

content/child/webthemeengine_impl_default.h

Index: content/child/webthemeengine_impl_default.h
diff --git a/content/child/webthemeengine_impl_default.h b/content/child/webthemeengine_impl_default.h
index b757d441b39955ccc186443de7f5bb69c89c3ce1..5fd96ed36f37ac3990bfb4be78afef6fe1f1893d 100644
--- a/content/child/webthemeengine_impl_default.h
+++ b/content/child/webthemeengine_impl_default.h
@@ -25,6 +25,33 @@ class WebThemeEngineImpl : public blink::WebThemeEngine {
                                     blink::WebThemeEngine::State endState,
                                     double progress,
                                     const blink::WebRect& rect);
+
+  // The next 4 functions are only invoked on Windows.

[jam, 2015/04/03 15:08:19]

why not behind OS_WIN?

[ananta, 2015/04/03 19:17:04]

Done.

+
+  // Caches the vertical scrollbar width.
+  static void SetVerticalScrollbarWidth(int32 vertical_scroll_bar_width);
+
+  // Caches the horizontal scrollbar height.
+  static void SetHorizontalScrollbarHeight(int32 horizontal_scroll_bar_height);
+
+  // Caches the vertical scrollbar arrow bitmap.
+  static void SetVerticalArrowBitmapHeight(int32 vertical_arrow_bitmap_height);
+
+  // Caches the horizontal scrollbar arrow bitmap.
+  static void SetHorizontalArrowBitmapWidth(int32 horizontal_arrow_bitmap_width);

[jam, 2015/04/03 15:08:19]

nit 80 chars

[ananta, 2015/04/03 19:17:04]

The four functions here have been collapsed to one function
CacheScrollBarMetrics.

+
+ private:
+  // The width of a vertical scroll bar in dips.
+  static int32 vertical_scroll_bar_width_;

[jam, 2015/04/03 15:08:19]

nit: i think the convention is to put these as globals in an anonymous
namespace?

[ananta, 2015/04/03 19:17:04]

Done.

+
+  // The height of a horizontal scroll bar in dips.
+  static int32 horizontal_scroll_bar_height_;
+
+  // The height of the arrow bitmap on a vertical scroll bar in dips.
+  static int32 vertical_arrow_bitmap_height_;
+
+  // The width of the arrow bitmap on a horizontal scroll bar in dips.
+  static int32 horizontal_arrow_bitmap_width_;
 };
 
 }  // namespace content