[Chrome OS MD] Update the color of update button and improve its appearance

ash/common/system/update/tray_update.cc

Index: ash/common/system/update/tray_update.cc
diff --git a/ash/common/system/update/tray_update.cc b/ash/common/system/update/tray_update.cc
index 42666496ef8770a2b5c9f059fe9c1d75a6ced018..b4ae32a480a3d2bdcc12f6cdd6ec41e28a717edf 100644
--- a/ash/common/system/update/tray_update.cc
+++ b/ash/common/system/update/tray_update.cc
@@ -15,6 +15,7 @@
 #include "ash/resources/vector_icons/vector_icons.h"
 #include "grit/ash_resources.h"
 #include "grit/ash_strings.h"
+#include "third_party/skia/include/core/SkColor.h"

[tdanderson, 2016/09/22 14:38:20]

This can be removed once the other comment is addressed.

[yiyix, 2016/09/22 18:31:10]

Done.

 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/color_palette.h"
 #include "ui/gfx/image/image.h"
@@ -64,7 +65,7 @@ SkColor IconColorForUpdateSeverity(UpdateInfo::UpdateSeverity severity,
     case UpdateInfo::UPDATE_NONE:
       return default_color;
     case UpdateInfo::UPDATE_LOW:
-      return for_menu ? gfx::kGoogleGreen700 : gfx::kGoogleGreen300;
+      return for_menu ? gfx::kGoogleGreen700 : SK_ColorWHITE;

[tdanderson, 2016/09/22 14:38:20]

nit: please use kTrayIconColor.

[yiyix, 2016/09/22 18:31:10]

I was just checking the constant with color white. I agree that kTrayIconColor
is more descriptive and better.

     case UpdateInfo::UPDATE_ELEVATED:
       return for_menu ? gfx::kGoogleYellow700 : gfx::kGoogleYellow300;
     case UpdateInfo::UPDATE_HIGH: