Fix user options for fractional digits in Intl.NumberFormatter

The patch in https://crrev.com/ddb5c2d999c5ee6e31c4a9599bb3ddb293cc3f49
moved all fractional digit settings to default values due to a coding
error. These were not even correct default values, and users observed
errors where percentages were written as "23.0%" instead of "23%".

This patch fixes the setting propagation when appropriate and it changes
the default max fractional digits of a percentage to 0, per spec.

BUG=chromium:544122
R=mnita,jochen
CC=hichris123,adamk
LOG=Y

Review URL: https://codereview.chromium.org/1420883002

Cr-Commit-Position: refs/heads/master@{#31468}

src/js/i18n.js

@@ -1107,14 +1107,15 @@ function initializeNumberFormat(numberFormat, locales, options) {
 
   var mnfd = options['minimumFractionDigits'];
   var mxfd = options['maximumFractionDigits'];
-  if (!IS_UNDEFINED(mnfd) || !internalOptions.style === 'currency') {
+  if (!IS_UNDEFINED(mnfd) || internalOptions.style !== 'currency') {
     mnfd = getNumberOption(options, 'minimumFractionDigits', 0, 20, 0);
     defineWEProperty(internalOptions, 'minimumFractionDigits', mnfd);
   }
 
-  if (!IS_UNDEFINED(mxfd) || !internalOptions.style === 'currency') {
+  if (!IS_UNDEFINED(mxfd) || internalOptions.style !== 'currency') {
+    var min_mxfd = internalOptions.style === 'percent' ? 0 : 3;
     mnfd = IS_UNDEFINED(mnfd) ? 0 : mnfd;
-    fallback_limit = (mnfd > 3) ? mnfd : 3;
+    fallback_limit = (mnfd > min_mxfd) ? mnfd : min_mxfd;
     mxfd = getNumberOption(options, 'maximumFractionDigits', mnfd, 20, fallback_limit);
     defineWEProperty(internalOptions, 'maximumFractionDigits', mxfd);
   }

test/intl/number-format/check-minimum-fraction-digits.js

@@ -2,8 +2,56 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Make sure minimumFractionDigits is honored
+// Make sure minimumFractionDigits and maximumFractionDigits are honored
 
-var nf = new Intl.NumberFormat("en-us",{ useGrouping: false, minimumFractionDigits: 4});
+var nf = new Intl.NumberFormat("en-us", { useGrouping: false, minimumFractionDigits: 4, maximumFractionDigits: 8});
 
 assertEquals("12345.6789", nf.format(12345.6789));
+assertEquals("12345.678912", nf.format(12345.678912));
+assertEquals("12345.6700", nf.format(12345.67));
+assertEquals("12345.67891234", nf.format(12345.6789123421));
+
+nf = new Intl.NumberFormat("en-us", { useGrouping: false, minimumFractionDigits: 4, maximumFractionDigits: 8, style: 'percent'});
+
+assertEquals("12345.6789%", nf.format(123.456789));
+assertEquals("12345.678912%", nf.format(123.45678912));
+assertEquals("12345.6700%", nf.format(123.4567));
+assertEquals("12345.67891234%", nf.format(123.456789123421));
+
+nf = new Intl.NumberFormat('en', {minimumFractionDigits: 4, maximumFractionDigits: 8, style: 'currency', currency: 'USD'});
+
+assertEquals("$54,306.404797", nf.format(54306.4047970));
+assertEquals("$54,306.4000", nf.format(54306.4));
+assertEquals("$54,306.40000001", nf.format(54306.400000011));
+
+// Ensure that appropriate defaults exist when minimum and maximum are not specified
+
+nf = new Intl.NumberFormat("en-us", { useGrouping: false });
+
+assertEquals("12345.679", nf.format(12345.6789));
+assertEquals("12345.679", nf.format(12345.678912));
+assertEquals("12345.67", nf.format(12345.6700));
+assertEquals("12345", nf.format(12345));
+assertEquals("12345.679", nf.format(12345.6789123421));
+
+nf = new Intl.NumberFormat("en-us", { useGrouping: false, style: 'percent'});
+
+assertEquals("12346%", nf.format(123.456789));
+assertEquals("12346%", nf.format(123.45678912));
+assertEquals("12346%", nf.format(123.456700));
+assertEquals("12346%", nf.format(123.456789123421));
+assertEquals("12345%", nf.format(123.45));
+
+// For currency, the minimum or the maximum can be overwritten individually
+
+nf = new Intl.NumberFormat('en', {minimumFractionDigits: 0, style: 'currency', currency: 'USD'});
+
+assertEquals("$54,306.4", nf.format(54306.4047970));
+assertEquals("$54,306.4", nf.format(54306.4));
+assertEquals("$54,306", nf.format(54306));
+
+nf = new Intl.NumberFormat('en', {maximumFractionDigits: 3, style: 'currency', currency: 'USD'});
+
+assertEquals("$54,306.405", nf.format(54306.4047970));
+assertEquals("$54,306.40", nf.format(54306.4));
+assertEquals("$54,306.00", nf.format(54306));