[Win, Linux] Always display the avatar button text at the same size.

ui/gfx/font_list.cc

Index: ui/gfx/font_list.cc
diff --git a/ui/gfx/font_list.cc b/ui/gfx/font_list.cc
index 920204bf7a74dcc0c7bd58e73242846852b989d0..b461aa9b28b0eb7f06fb65931bf2f9f9b4c4bb0d 100644
--- a/ui/gfx/font_list.cc
+++ b/ui/gfx/font_list.cc
@@ -106,6 +106,27 @@ const Font& FontList::GetPrimaryFont() const {
   return impl_->GetPrimaryFont();
 }
 
+gfx::FontList FontList::GetLargestFontListWithHeightBound(int height) const {
+  gfx::FontList font_list(*this);
+  for (int font_size = font_list.GetFontSize(); font_size > 1; --font_size) {
+    const int internal_leading =
+        font_list.GetBaseline() - font_list.GetCapHeight();
+    // Some platforms don't support getting the cap height, and simply return
+    // the entire font ascent from GetCapHeight().  Centering the ascent makes
+    // the font look too low, so if GetCapHeight() returns the ascent, center
+    // the entire font height instead.
+    const int space =
+        height - ((internal_leading != 0) ?
+                  font_list.GetCapHeight() : font_list.GetHeight());
+    const int y_offset = space / 2 - internal_leading;
+    const int space_at_bottom = height - (y_offset + font_list.GetHeight());
+    if ((y_offset >= 0) && (space_at_bottom >= 0))
+      break;
+    font_list = font_list.DeriveWithSizeDelta(-1);
+  }
+  return font_list;
+}
+
 FontList::FontList(FontListImpl* impl) : impl_(impl) {}
 
 // static