Refactor ViewsDelegate and MD-ify the icon-to-text spacing for checkbox and radiobutton

ui/views/controls/button/label_button.cc

Index: ui/views/controls/button/label_button.cc
diff --git a/ui/views/controls/button/label_button.cc b/ui/views/controls/button/label_button.cc
index 4a7cfd912fab2b1bdd0ce463176fc6b501408a15..028c4710a5d229dedb6e0b80ca9290327018c242 100644
--- a/ui/views/controls/button/label_button.cc
+++ b/ui/views/controls/button/label_button.cc
@@ -25,15 +25,14 @@
 #include "ui/views/animation/square_ink_drop_ripple.h"
 #include "ui/views/background.h"
 #include "ui/views/controls/button/label_button_border.h"
+#include "ui/views/layout/layout_constants.h"
 #include "ui/views/painter.h"
 #include "ui/views/style/platform_style.h"
+#include "ui/views/views_delegate.h"
 #include "ui/views/window/dialog_delegate.h"
 
 namespace {
 
-// The default spacing between the icon and text.
-const int kSpacing = 5;
-
 gfx::Font::Weight GetValueBolderThan(gfx::Font::Weight weight) {
   if (weight < gfx::Font::Weight::BOLD)
     return gfx::Font::Weight::BOLD;
@@ -93,7 +92,8 @@ LabelButton::LabelButton(ButtonListener* listener, const base::string16& text)
       is_default_(false),
       style_(STYLE_TEXTBUTTON),
       border_is_themed_border_(true),
-      image_label_spacing_(kSpacing),
+      image_label_spacing_(ViewsDelegate::GetInstance()->GetDistanceMetric(
+          DistanceMetric::RELATED_CONTROL_HORIZONTAL)),
       horizontal_alignment_(gfx::ALIGN_LEFT) {
   SetAnimationDuration(kHoverAnimationDurationMs);
   SetTextInternal(text);