For some vector icons, get the size from the vector definition.

chrome/browser/ui/views/toolbar/app_menu_button.cc

Index: chrome/browser/ui/views/toolbar/app_menu_button.cc
diff --git a/chrome/browser/ui/views/toolbar/app_menu_button.cc b/chrome/browser/ui/views/toolbar/app_menu_button.cc
index 450e8f9b5637c098f4524e25dcf93d1693d1b3c0..ca12f2f1d1dd190b9bbe03d43558d92d344fc758 100644
--- a/chrome/browser/ui/views/toolbar/app_menu_button.cc
+++ b/chrome/browser/ui/views/toolbar/app_menu_button.cc
@@ -151,11 +151,8 @@ void AppMenuButton::UpdateIcon() {
       break;
   }
 
-  // TODO(estade): find a home for this constant.
-  const int kButtonSize = 16;
   SetImage(views::Button::STATE_NORMAL,
-           gfx::CreateVectorIcon(gfx::VectorIconId::BROWSER_TOOLS, kButtonSize,
-                                 color));
+           gfx::CreateVectorIcon(gfx::VectorIconId::BROWSER_TOOLS, color));
 }
 
 void AppMenuButton::SetTrailingMargin(int margin) {