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

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

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/toolbar/app_menu_button.h"
 
 #include "base/location.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/thread_task_runner_handle.h"
@@ skipping 133 matching lines @@
       color = gfx::kGoogleGreen700;
       break;
     case AppMenuIconPainter::SEVERITY_MEDIUM:
       color = gfx::kGoogleYellow700;
       break;
     case AppMenuIconPainter::SEVERITY_HIGH:
       color = gfx::kGoogleRed700;
       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) {
   margin_trailing_ = margin;
 
   UpdateThemedBorder();
 
   const int inset = LabelButton::kFocusRectInset;
   SetFocusPainter(views::Painter::CreateDashedFocusPainterWithInsets(
       gfx::Insets(inset, inset, inset, inset + margin)));
@@ skipping 78 matching lines @@
   views::MenuButton::OnPaint(canvas);
   if (ui::MaterialDesignController::IsModeMaterial())
     return;
   // Use GetPreferredSize() to center the icon inside the visible bounds rather
   // than the whole size() (which may refer to hit test region extended to the
   // end of the toolbar in maximized mode).
   icon_painter_->Paint(canvas, GetThemeProvider(),
                        gfx::Rect(GetPreferredSize()),
                        AppMenuIconPainter::BEZEL_NONE);
 }