Add '#' to SafeStyle list of allowed characters inside functions. The fix enables to use the HEX color format in functions like linear-gradient().

https://developer.mozilla.org/en-US/docs/Web/CSS/gradient/linear-gradient()

RELNOTES: Add '#' to SafeStyle list of allowed characters inside functions.
PiperOrigin-RevId: 402361256
Change-Id: Ib3144a91f94509015ddee246ea41d8bc265c721e

Author: Closure Team

closure/goog/html/safestyle.js

@@ -544,7 +544,7 @@ const ALLOWED_FUNCTIONS = [
  */
 const FUNCTIONS_RE = new RegExp(
     '\\b(' + ALLOWED_FUNCTIONS.join('|') + ')' +
-        '\\([-+*/0-9a-z.%\\[\\], ]+\\)',
+        '\\([-+*/0-9a-z.%#\\[\\], ]+\\)',
     'g');
 
 

closure/goog/html/safestyle_test.js

@@ -185,6 +185,18 @@ testSuite({
         {'color': 'var(--xyz, black)'});
   },
 
+  testCreate_allowsLinearGradient() {
+    assertCreateEquals(
+        'background:linear-gradient(red, blue);',
+        {'background': 'linear-gradient(red, blue)'});
+    assertCreateEquals(
+        'background:linear-gradient(rgb(10,0,0), rgb(0,0,30));',
+        {'background': 'linear-gradient(rgb(10,0,0), rgb(0,0,30))'});
+    assertCreateEquals(
+        'background:linear-gradient(#333, #eee);',
+        {'background': 'linear-gradient(#333, #eee)'});
+  },
+
   testCreate_allowsSafeUrl() {
     assertCreateEquals('background:url("http://example.com");', {
       'background': SafeUrl.fromConstant(Const.from('http://example.com')),