First stab at touch optimized omnibox auto-complete per sgabriel's mocks.

ui/gfx/native_theme_aura.cc

Index: ui/gfx/native_theme_aura.cc
diff --git a/ui/gfx/native_theme_aura.cc b/ui/gfx/native_theme_aura.cc
index 51683513c0af0470fa9ba0480b65ee9cb91e937a..fc11fb9e1f56102e065c7d30562785239a223ac8 100644
--- a/ui/gfx/native_theme_aura.cc
+++ b/ui/gfx/native_theme_aura.cc
@@ -45,6 +45,9 @@ const SkColor kTextfieldSelectionBackgroundUnfocused = SK_ColorLTGRAY;
 const SkColor kTextfieldSelectionColor =
     color_utils::AlphaBlend(SK_ColorBLACK,
         kTextfieldSelectionBackgroundFocused, 0xdd);
+// Colors for 3D controls:
+const SkColor kThreeDLightShadow = SkColorSetRGB(0xE3, 0xE3, 0xE3);
+const SkColor kThreeDShadow = SkColorSetRGB(0xA0, 0xA0, 0xA0);
 
 }  // namespace
 
@@ -123,6 +126,12 @@ SkColor NativeThemeAura::GetSystemColor(ColorId color_id) const {
     case kColorId_TextfieldSelectionBackgroundUnfocused:
       return kTextfieldSelectionBackgroundUnfocused;
 
+    // Colors for 3D controls
+    case kColorId_ThreeDLightShadow:
+      return kThreeDLightShadow;
+    case kColorId_ThreeDShadow:
+      return kThreeDShadow;
+
     default:
       NOTREACHED() << "Invalid color_id: " << color_id;
       break;