Make it possible for downstream projects to easily set the default fill color

content/public/common/web_preferences.cc

Index: content/public/common/web_preferences.cc
diff --git a/content/public/common/web_preferences.cc b/content/public/common/web_preferences.cc
index f0703241c5f604f3a7d9c342d0ee8bc9a0c80a99..598bb5bda095c2d70939185bcb2fee09d5d6b958 100644
--- a/content/public/common/web_preferences.cc
+++ b/content/public/common/web_preferences.cc
@@ -8,6 +8,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "third_party/WebKit/public/web/WebSettings.h"
+#include "third_party/skia/include/core/SkColor.h"
 
 using blink::WebSettings;
 
@@ -63,6 +64,10 @@ STATIC_ASSERT_ENUM(ViewportStyle::MOBILE, blink::WebViewportStyle::Mobile);
 STATIC_ASSERT_ENUM(ViewportStyle::TELEVISION,
                    blink::WebViewportStyle::Television);
 
+#ifndef DEFAULT_BACKGROUND_COLOR
+#define DEFAULT_BACKGROUND_COLOR SK_ColorWHITE
+#endif
+
 WebPreferences::WebPreferences()
     : default_font_size(16),
       default_fixed_font_size(13),
@@ -154,6 +159,7 @@ WebPreferences::WebPreferences()
       editing_behavior(EDITING_BEHAVIOR_MAC),
 #endif
       supports_multiple_windows(true),
+      default_background_color(DEFAULT_BACKGROUND_COLOR),
       viewport_enabled(false),
 #if defined(OS_ANDROID)
       viewport_meta_enabled(true),