Directly inline shared WebUI CSS declarations into the security and supervised user interstitials.

ui/base/webui/web_ui_util.h

Index: ui/base/webui/web_ui_util.h
diff --git a/ui/base/webui/web_ui_util.h b/ui/base/webui/web_ui_util.h
index 84e06f3170be5d3e336a932458efc5d5447f4f25..5db9f33c10cfbcd0987bab245b77b56b88e82add 100644
--- a/ui/base/webui/web_ui_util.h
+++ b/ui/base/webui/web_ui_util.h
@@ -45,10 +45,19 @@ UI_BASE_EXPORT void ParsePathAndScale(const GURL& url,
                                       std::string* path,
                                       float* scale_factor);
 
-// Helper function to set the font family, size, and text direction into the
-// given dictionary.
-UI_BASE_EXPORT void SetFontAndTextDirection(
-    base::DictionaryValue* localized_strings);
+// Helper function to set the text direction on the given dictionary.
+// Note that while this method will also set attributes for default font size
+// and family, using those in JS templates is deprecated, because it might lead
+// to flicker. Instead, use AppendWebUiCssTextDefaults() below.
+// TODO(bauerb): Remove uses of font-family and font-size in JS templates.
+UI_BASE_EXPORT void SetTextDirection(base::DictionaryValue* localized_strings);

[Dan Beam, 2015/01/22 17:08:41]

nit: rename this when it only sets text direction (it still sets font stuff
too...)

[Bernhard Bauer, 2015/01/22 17:36:17]

Hm, I did that on purpose now instead of later, so that people wouldn't use it
in more places to set the font attributes, when we want to get rid of the
existing places :)

[Dan Beam, 2015/01/22 17:47:58]

i can see both points of view here, but i've always been told "plan for later,
code for now".  just a nit.

[Bernhard Bauer, 2015/01/23 11:57:49]

Fair enough. Done!

+
+// Get a CSS declaration for common text styles for all of Web UI.
+UI_BASE_EXPORT std::string GetWebUiCssTextDefaults();
+
+// Appends the CSS declaration returned by GetWebUiCssTextDefaults() as an
+// inline stylesheet.
+UI_BASE_EXPORT void AppendWebUiCssTextDefaults(std::string* html);
 
 // Get some common font styles for all of WebUI.
 UI_BASE_EXPORT std::string GetFontFamily();