[Template Expressions] changing ${ leader to $i18n{

This CL changes the Template Expressions from using
a ${ to identify the start of an expression, to using
$i18n{.  The intention is to reduce (eliminate) false
positives when searching for expressions that need
replacement.  This CL also prepares for the replacement
work to be done in a background thread and used on a
broader set of files.

BUG=506009

Review URL: https://codereview.chromium.org/1585923011

Cr-Commit-Position: refs/heads/master@{#371537}

chrome/browser/resources/ntp4/new_incognito_tab_theme.css

@@ -5,21 +5,21 @@
 
 html {
   background-attachment: fixed;
-  background-color: ${colorBackground};
-  background-position: ${backgroundBarDetached};
-  background-repeat: ${backgroundTiling};
+  background-color: $i18n{colorBackground};
+  background-position: $i18n{backgroundBarDetached};
+  background-repeat: $i18n{backgroundTiling};
   height: 100%;
   overflow: auto;
 }
 
 html[hascustombackground='true'] {
-  background-image: url(chrome://theme/IDR_THEME_NTP_BACKGROUND?${themeId});
+  background-image: url(chrome://theme/IDR_THEME_NTP_BACKGROUND?$i18n{themeId});
 }
 
 html[bookmarkbarattached='true'] {
-  background-position: ${backgroundBarAttached};
+  background-position: $i18n{backgroundBarAttached};
 }
 
 #attribution-img {
-  content: url(chrome://theme/IDR_THEME_NTP_ATTRIBUTION?${themeId});
+  content: url(chrome://theme/IDR_THEME_NTP_ATTRIBUTION?$i18n{themeId});
 }

chrome/browser/resources/ntp4/new_tab_theme.css

-/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
+/* Copyright 2012 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. */
 
 html {
   background-attachment: fixed;
-  background-color: ${colorBackground};
-  background-image: url(chrome://theme/IDR_THEME_NTP_BACKGROUND?${themeId});
-  background-position: ${backgroundBarDetached};
-  background-repeat: ${backgroundTiling};
+  background-color: $i18n{colorBackground};
+  background-image: url(chrome://theme/IDR_THEME_NTP_BACKGROUND?$i18n{themeId});
+  background-position: $i18n{backgroundBarDetached};
+  background-repeat: $i18n{backgroundTiling};
 }
 
 #attribution {
-  left: ${leftAlignAttribution};
-  right: ${rightAlignAttribution};
-  text-align: ${textAlignAttribution};
-  display: ${displayAttribution};
+  left: $i18n{leftAlignAttribution};
+  right: $i18n{rightAlignAttribution};
+  text-align: $i18n{textAlignAttribution};
+  display: $i18n{displayAttribution};
 }
 
 #attribution-img {
-  content: url(chrome://theme/IDR_THEME_NTP_ATTRIBUTION?${themeId});
+  content: url(chrome://theme/IDR_THEME_NTP_ATTRIBUTION?$i18n{themeId});
 }
 
 html[bookmarkbarattached='true'] {
-  background-position: ${backgroundBarAttached};
+  background-position: $i18n{backgroundBarAttached};
 }
 
 body {
-  color: ${colorTextRgba};
+  color: $i18n{colorTextRgba};
   height: 100%;
   overflow: auto;
 }
 
 #attribution,
 [is='action-link'] {
-  color: ${colorTextLight};
+  color: $i18n{colorTextLight};
 }
 
 [is='action-link']:active {
-  color: ${colorTextRgba};
+  color: $i18n{colorTextRgba};
 }
 
 .page-switcher {
-  color: rgba(${colorText}, 0.5);
+  color: rgba($i18n{colorText}, 0.5);
 }
 
 .page-switcher:hover,
 .page-switcher:focus,
 .page-switcher.drag-target {
-  background-color: rgba(${colorText}, 0.06);
+  background-color: rgba($i18n{colorText}, 0.06);
 }
 
 /* Only change the background to a gradient when a promo is showing. */
@@ -55,34 +55,34 @@ body {
 .showing-login-area #page-switcher-end:focus,
 .showing-login-area #page-switcher-end.drag-target {
   background: linear-gradient(top,
-      rgba(${colorText}, 0) 0,
-      rgba(${colorText}, .01) 60px,
-      rgba(${colorText}, .06) 183px);
+      rgba($i18n{colorText}, 0) 0,
+      rgba($i18n{colorText}, .01) 60px,
+      rgba($i18n{colorText}, .06) 183px);
 }
 
 .tile-page-scrollbar {
-  background-color: ${colorTextLight};
+  background-color: $i18n{colorTextLight};
 }
 
 /* Footer *********************************************************************/
 
 #footer-border {
   background: linear-gradient(left,
-      rgba(${colorSectionBorder}, 0.2),
-      rgba(${colorSectionBorder}, 0.3) 20%,
-      rgba(${colorSectionBorder}, 0.3) 80%,
-      rgba(${colorSectionBorder}, 0.2));
+      rgba($i18n{colorSectionBorder}, 0.2),
+      rgba($i18n{colorSectionBorder}, 0.3) 20%,
+      rgba($i18n{colorSectionBorder}, 0.3) 80%,
+      rgba($i18n{colorSectionBorder}, 0.2));
 }
 
 .dot input:focus {
-  background-color: ${colorBackground};
+  background-color: $i18n{colorBackground};
 }
 
 .thumbnail-wrapper {
   /* This shows through at the (rounded) thumbnail's corners. */
-  background-color: ${colorSectionBorder};
+  background-color: $i18n{colorSectionBorder};
 }
 
 .filler .thumbnail {
-  border-color: ${colorBackground};
+  border-color: $i18n{colorBackground};
 }

chrome/browser/ui/webui/ntp/ntp_resource_cache.cc

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright 2012 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.
 
@@ -553,7 +553,7 @@ void NTPResourceCache::CreateNewTabIncognitoCSS() {
           : SkColorSetRGB(0x32, 0x32, 0x32);
 
   // Generate the replacements.
-  std::map<base::StringPiece, std::string> substitutions;
+  ui::TemplateReplacements substitutions;
 
   // Cache-buster for background.
   substitutions["themeId"] =
@@ -605,7 +605,7 @@ void NTPResourceCache::CreateNewTabCSS() {
                      SkColorGetB(color_header));
 
   // Generate the replacements.
-  std::map<base::StringPiece, std::string> substitutions;
+  ui::TemplateReplacements substitutions;
 
   // Cache-buster for background.
   substitutions["themeId"] =

chrome/browser/web_dev_style/css_checker.py

-# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Copyright 2012 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.
 
@@ -52,7 +52,7 @@ class CSSChecker(object):
       return re.sub(re.compile(r'--[\d\w-]+: {.*?};', re.DOTALL), '', s)
 
     def _remove_template_expressions(s):
-      return re.sub(re.compile(r'\${[^}]*}', re.DOTALL), '', s)
+      return re.sub(re.compile(r'\$i18n{[^}]*}', re.DOTALL), '', s)
 
     def _remove_grit(s):
       grit_reg = re.compile(r"""

ui/base/template_expressions.cc

@@ -8,29 +8,36 @@
 
 #include "base/logging.h"
 
+namespace {
+const char kLeader[] = "$i18n{";
+const size_t kLeaderSize = arraysize(kLeader) - 1;
+const char kTail[] = "}";
+const size_t kTailSize = arraysize(kTail) - 1;
+}   // namespace
+
 namespace ui {
 
 std::string ReplaceTemplateExpressions(
     base::StringPiece format_string,
-    const std::map<base::StringPiece, std::string>& substitutions) {
+    const TemplateReplacements& substitutions) {
   std::string formatted;
   const size_t kValueLengthGuess = 16;
   formatted.reserve(format_string.length() +
                     substitutions.size() * kValueLengthGuess);
   base::StringPiece::const_iterator i = format_string.begin();
   while (i < format_string.end()) {
-    if (*i == '$' && i + 2 < format_string.end() && i[1] == '{' &&
-        i[2] != '}') {
-      size_t key_start = i + strlen("${") - format_string.begin();
-      size_t key_length = format_string.find('}', key_start);
+    if (base::StringPiece(i).starts_with(kLeader)) {
+      size_t key_start = i + kLeaderSize - format_string.begin();
+      size_t key_length = format_string.find(kTail, key_start);
       if (key_length == base::StringPiece::npos)
-        NOTREACHED() << "TemplateExpression missing ending brace '}'";
+        NOTREACHED() << "TemplateExpression missing ending tag";
       key_length -= key_start;
-      base::StringPiece key(format_string.begin() + key_start, key_length);
+      std::string key(format_string.begin() + key_start, key_length);
+      DCHECK(!key.empty());
       const auto& replacement = substitutions.find(key);
       if (replacement != substitutions.end()) {
         formatted.append(replacement->second);
-        i += strlen("${") + key_length + strlen("}");
+        i += kLeaderSize + key_length + kTailSize;
         continue;
       } else {
         NOTREACHED() << "TemplateExpression key not found: " << key;

ui/base/template_expressions.h

@@ -16,12 +16,15 @@
 
 namespace ui {
 
+// Map of strings for template replacement in |ReplaceTemplateExpressions|.
+typedef std::map<const std::string, std::string> TemplateReplacements;
+
 // Replace ${foo} in the format string with the value for the foo key in
 // |subst|.  If the key is not found in the |substitutions| that item will
 // be unaltered.
 UI_BASE_EXPORT std::string ReplaceTemplateExpressions(
     base::StringPiece format_string,
-    const std::map<base::StringPiece, std::string>& substitutions);
+    const TemplateReplacements& substitutions);
 
 }  // namespace ui
 

ui/base/template_expressions_unittest.cc

@@ -9,27 +9,26 @@
 namespace ui {
 
 TEST(TemplateExpressionsTest, ReplaceTemplateExpressionsPieces) {
-  std::map<base::StringPiece, std::string> substitutions;
+  TemplateReplacements substitutions;
   substitutions["test"] = "word";
   substitutions["5"] = "number";
 
-  EXPECT_EQ("${}", ReplaceTemplateExpressions("${}", substitutions));
   EXPECT_EQ("", ReplaceTemplateExpressions("", substitutions));
-  EXPECT_EQ("word", ReplaceTemplateExpressions("${test}", substitutions));
-  EXPECT_EQ("number ", ReplaceTemplateExpressions("${5} ", substitutions));
-  EXPECT_EQ(
-      "multiple: word, number.",
-      ReplaceTemplateExpressions("multiple: ${test}, ${5}.", substitutions));
+  EXPECT_EQ("word", ReplaceTemplateExpressions("$i18n{test}", substitutions));
+  EXPECT_EQ("number ", ReplaceTemplateExpressions("$i18n{5} ", substitutions));
+  EXPECT_EQ("multiple: word, number.",
+            ReplaceTemplateExpressions("multiple: $i18n{test}, $i18n{5}.",
+                                       substitutions));
 }
 
 TEST(TemplateExpressionsTest,
      ReplaceTemplateExpressionsConsecutiveDollarSignsPieces) {
-  std::map<base::StringPiece, std::string> substitutions;
+  TemplateReplacements substitutions;
   substitutions["a"] = "x";
   EXPECT_EQ("$ $$ $$$", ReplaceTemplateExpressions("$ $$ $$$", substitutions));
-  EXPECT_EQ("$x", ReplaceTemplateExpressions("$${a}", substitutions));
-  EXPECT_EQ("$$x", ReplaceTemplateExpressions("$$${a}", substitutions));
-  EXPECT_EQ("$12", ReplaceTemplateExpressions("$12", substitutions));
+  EXPECT_EQ("$x", ReplaceTemplateExpressions("$$i18n{a}", substitutions));
+  EXPECT_EQ("$$x", ReplaceTemplateExpressions("$$$i18n{a}", substitutions));
+  EXPECT_EQ("$i18n12", ReplaceTemplateExpressions("$i18n12", substitutions));
 }
 
 }  // namespace ui

ui/base/webui/web_ui_util.cc

@@ -123,7 +123,7 @@ void SetLoadTimeDataDefaults(const std::string& app_locale,
 }
 
 std::string GetWebUiCssTextDefaults(const std::string& css_template) {
-  std::map<base::StringPiece, std::string> placeholders;
+  ui::TemplateReplacements placeholders;
   placeholders["textDirection"] = GetTextDirection();
   placeholders["fontFamily"] = GetFontFamily();
   placeholders["fontSize"] = GetFontSize();

ui/webui/resources/css/text_defaults.css

@@ -16,14 +16,14 @@
  * Otherwise its $placeholders won't be expanded. */
 
 html {
-  direction: ${textDirection};
+  direction: $i18n{textDirection};
 }
 
 body {
-  font-family: ${fontFamily};
-  font-size: ${fontSize};
+  font-family: $i18n{fontFamily};
+  font-size: $i18n{fontSize};
 }
 
 button {
-  font-family: ${fontFamily};
+  font-family: $i18n{fontFamily};
 }