[Extensions UI] Tweak the constants for extension action grayscaling

chrome/browser/ui/extensions/icon_with_badge_image_source.cc

 // Copyright (c) 2012 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/extensions/icon_with_badge_image_source.h"
 
 #include <algorithm>
 #include <cmath>
 #include <utility>
 
@@ skipping 120 matching lines @@
   if (icon_.IsEmpty())
     return;
 
   gfx::ImageSkia skia = icon_.AsImageSkia();
   gfx::ImageSkiaRep rep = skia.GetRepresentation(canvas->image_scale());
   if (rep.scale() != canvas->image_scale()) {
     skia.AddRepresentation(ScaleImageSkiaRep(
         rep, ExtensionAction::ActionIconSize(), canvas->image_scale()));
   }
   if (grayscale_)
-    skia = gfx::ImageSkiaOperations::CreateHSLShiftedImage(skia, {-1, 0, 0.6});
+    skia = gfx::ImageSkiaOperations::CreateHSLShiftedImage(skia, {-1, 0, 0.75});
 
   int x_offset =
       std::floor((size().width() - ExtensionAction::ActionIconSize()) / 2.0);
   int y_offset =
       std::floor((size().height() - ExtensionAction::ActionIconSize()) / 2.0);
   canvas->DrawImageInt(skia, x_offset, y_offset);
 
   // Draw a badge on the provided browser action icon's canvas.
   PaintBadge(canvas);
 
@@ skipping 137 matching lines @@
 }
 
 void IconWithBadgeImageSource::PaintBlockedActionDecoration(
     gfx::Canvas* canvas) {
   canvas->Save();
   gfx::ImageSkia img = *ResourceBundle::GetSharedInstance().GetImageSkiaNamed(
       IDR_BLOCKED_EXTENSION_SCRIPT);
   canvas->DrawImageInt(img, size().width() - img.width(), 0);
   canvas->Restore();
 }