MD Downloads/History: unify page and toolbar background colors

ui/webui/resources/css/md_colors.css

Index: ui/webui/resources/css/md_colors.css
diff --git a/ui/webui/resources/css/md_colors.css b/ui/webui/resources/css/md_colors.css
new file mode 100644
index 0000000000000000000000000000000000000000..afb4455d731d92634ce8346756801b456f4b2957
--- /dev/null
+++ b/ui/webui/resources/css/md_colors.css
@@ -0,0 +1,10 @@
+/* Copyright 2016 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. */
+
+:root {
+  /* These are custom, Chrome-specific colors that don't have --paper or
+   * --google equivalents. Blame bettes@. http://crbug.com/598451 */
+  --md-background-color: rgb(236, 239, 241);
+  --md-toolbar-color: rgb(52, 73, 94);
+}