partly import changes from tenfourfox:

- #482: better bidi M1358275 M1392181 M1428774 + backbugs (e88a717ab)
- M1739352 M1732572(partial) M1717318(partial) M1586061 (03ffdeadb)
- M1737515 M1737470(no tests) +TLDs, tzdata (fd2b82f13)

intl/unicharutil/util/nsBidiUtils.cpp

@@ -5,6 +5,10 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "nsBidiUtils.h"
 
+namespace mozilla {
+static const uint32_t kMinRTLChar = 0x0590;
+} // namespace mozilla;
+
 #define ARABIC_TO_HINDI_DIGIT_INCREMENT (START_HINDI_DIGITS - START_ARABIC_DIGITS)
 #define PERSIAN_TO_HINDI_DIGIT_INCREMENT (START_HINDI_DIGITS - START_FARSI_DIGITS)
 #define ARABIC_TO_PERSIAN_DIGIT_INCREMENT (START_FARSI_DIGITS - START_ARABIC_DIGITS)
@@ -82,16 +86,18 @@ nsresult HandleNumbers(char16_t* aBuffer, uint32_t aSize, uint32_t aNumFlag)
   return NS_OK;
 }
 
-bool HasRTLChars(const nsAString& aString)
+bool HasRTLChars(const char16_t* aText, uint32_t aLength)
 {
-// This is used to determine whether to enable bidi if a string has 
-// right-to-left characters. To simplify things, anything that could be a
-// surrogate or RTL presentation form is covered just by testing >= 0xD800).
-// It's fine to enable bidi in rare cases where it actually isn't needed.
-  int32_t length = aString.Length();
-  for (int32_t i = 0; i < length; i++) {
-    char16_t ch = aString.CharAt(i);
-    if (ch >= 0xD800 || IS_IN_BMP_RTL_BLOCK(ch)) {
+  // This is used to determine whether a string has right-to-left characters
+  // that mean it will require bidi processing.
+  const char16_t* cp = aText;
+  const char16_t* end = cp + aLength;
+  while (cp < end) {
+    char16_t ch = *cp++;
+    if (ch < mozilla::kMinRTLChar) {
+      continue;
+    }
+    if (UTF16_CODE_UNIT_IS_BIDI(ch) || IsBidiControlRTL(ch)) {
       return true;
     }
   }