[MD settings] i18n template replacements in shared HTML resources

ui/base/template_expressions.cc

Index: ui/base/template_expressions.cc
diff --git a/ui/base/template_expressions.cc b/ui/base/template_expressions.cc
index 10aaf4fecf5a4e44040c427de461ba5704336fbf..1fcee4ef55cb5432f5ccad3eb1df9c94004350ca 100644
--- a/ui/base/template_expressions.cc
+++ b/ui/base/template_expressions.cc
@@ -7,6 +7,7 @@
 #include <stddef.h>
 
 #include "base/logging.h"
+#include "base/values.h"
 #include "net/base/escape.h"
 
 namespace {
@@ -18,6 +19,31 @@ const char kKeyClose = '}';
 
 namespace ui {
 
+void TemplateReplacementsFromDictionaryValue(
+    const base::DictionaryValue& dictionary,
+    TemplateReplacements* replacements) {
+  for (base::DictionaryValue::Iterator it(dictionary); !it.IsAtEnd();
+       it.Advance()) {
+    if (it.value().IsType(base::Value::Type::STRING)) {
+      std::string str_value;
+      if (it.value().GetAsString(&str_value))
+        (*replacements)[it.key()] = str_value;
+    } else if (it.value().IsType(base::Value::Type::BOOLEAN)) {
+      bool bool_value;
+      if (it.value().GetAsBoolean(&bool_value))
+        TemplateReplacementsSetBool(it.key(), bool_value, replacements);
+    }
+  }
+}
+
+void TemplateReplacementsSetBool(const std::string& name,
+                                 bool value,
+                                 TemplateReplacements* replacements) {
+  // These are HTML Boolean attributes which are represented by their name
+  // if truthy and by complete absence (empty string) if falsy.

[Dan Beam, 2017/01/03 20:03:15]

this comment is confusing.

hidden="" hides stuff, and disabled="" disables.

https://jsfiddle.net/1ezdb6cs/

I think what you mean is that if setAttribute('blah', '') is called, a boolean
attribute is added (boolean attribute means no value).  if a value is processed
with a false value, we shouldn't be calling setAttribute().  as in, we should
drop a 2-liner into i18n_template_no_process.js after we've gotten the propName
and value:

if (value === false)
  continue;

and update any code that relies on this (i.e. CSS that looks for
=="true"/"false" or something).

https://cs.chromium.org/chromium/src/ui/webui/resources/js/i18n_template_no_p...

[dschuyler, 2017/01/03 20:36:56]

Correct, so in this case:

<div $i18n{guestMode}>...</div>

TemplateReplacementsSetBool("guestMode", true, ...) will add a guestMode
attribute and 

TemplateReplacementsSetBool("guestMode", false, ...) will not add a guestMode
attribute.

You make a good point about hidden and disabled though. Having a i18n tag of 
mplateReplacementsSetBool("hidden", true, ...) is not very specific (i.e. what's
being hidden).

For cases that need to be handled in JavaScript, the current loadTimeData will
continue to operate with actual true and false Boolean values.

+  (*replacements)[name] = value ? name : "";
+}
+
 std::string ReplaceTemplateExpressions(
     base::StringPiece source,
     const TemplateReplacements& replacements) {