util: Kill off rtrim() helper.

I am 99% sure we can rely on trimRight() and
trim() being available in all browsers that
we support.  I verified in FF.

This removes the util dependency from both
modules touched here.

frontend_tests/node_tests/util.js

@@ -39,12 +39,6 @@ run_test('is_pm_recipient', () => {
     assert(!util.is_pm_recipient('unknown@example.com', message));
 });
 
-run_test('rtrim', () => {
-    assert.equal(util.rtrim('foo'), 'foo');
-    assert.equal(util.rtrim('  foo'), '  foo');
-    assert.equal(util.rtrim('foo  '), 'foo');
-});
-
 run_test('lower_bound', () => {
     let arr = [10, 20, 30, 40, 50];
     assert.equal(util.lower_bound(arr, 5), 0);

static/js/compose_state.js

@@ -1,4 +1,3 @@
-const util = require("./util");
 let message_type = false; // 'stream', 'private', or false-y
 
 exports.set_message_type = function (msg_type) {
@@ -32,7 +31,7 @@ function get_or_set(fieldname, keep_leading_whitespace) {
         if (newval !== undefined) {
             elem.val(newval);
         }
-        return keep_leading_whitespace ? util.rtrim(oldval) : $.trim(oldval);
+        return keep_leading_whitespace ? oldval.trimRight() : oldval.trim();
     };
 }
 

static/js/fenced_code.js

@@ -1,4 +1,3 @@
-const util = require("./util");
 // Parsing routine that can be dropped in to message parsing
 // and formats code blocks
 //
@@ -116,7 +115,7 @@ exports.process_fenced_code = function (content) {
                     if (line === fence) {
                         this.done();
                     } else {
-                        lines.push(util.rtrim(line));
+                        lines.push(line.trimRight());
                     }
                 },
 

static/js/util.js

@@ -131,10 +131,6 @@ exports.robust_uri_decode = function (str) {
     return '';
 };
 
-exports.rtrim = function (str) {
-    return str.replace(/\s+$/, '');
-};
-
 // If we can, use a locale-aware sorter.  However, if the browser
 // doesn't support the ECMAScript Internationalization API
 // Specification, do a dumb string comparison because