input[type=color] should look like a button

- We should apply ButtonFace background instead of white.
- For fallback style, use |1px #a9a9a solid| border to match Aura buttons.
- Adjust paddings

BUG=360997
TEST=automated

Review URL: https://codereview.chromium.org/225413019

git-svn-id: svn://svn.chromium.org/blink/trunk@171032 bbb929c8-8fbe-4397-9dbb-9b2b20218538
diff --git a/Source/core/css/html.css b/Source/core/css/html.css
index 2e90588..fbe5a1e 100644
--- a/Source/core/css/html.css
+++ b/Source/core/css/html.css
@@ -793,6 +793,10 @@
     -webkit-appearance: square-button;
     width: 44px;
     height: 23px;
+    background-color: ButtonFace;
+    /* Same as native_theme_base. */
+    border: 1px #a9a9a9 solid;
+    padding: 1px 2px;
 }
 
 input[type="color"]::-webkit-color-swatch-wrapper {