Implement ES6 unicode escapes.

test/cctest/test-parsing.cc

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@@ skipping 4287 matching lines @@
   const char* context_data[][2] = {{"", ""},
                                    {"'use strict';", ""},
                                    {NULL, NULL}};
   const char* data[] = {
     "var foob\\u123r = 0;",
     "var \\u123roo = 0;",
     "\"foob\\u123rr\"",
     // No escapes allowed in regexp flags
     "/regex/\\u0069g",
     "/regex/\\u006g",
+    // Braces gone wrong
+    "var foob\\u{c481r = 0;",
+    "var foob\\uc481}r = 0;",
+    "var foob\\u{c4}r = 0;",
+    "var \\u{0052oo = 0;",
+    "var \\u0052}oo = 0;",
+    "var \\u{00}oo = 0;",
+    "\"foob\\u{c481r\"",
+    "\"foob\\u{c4}r\"",

[arv (Not doing code reviews), 2014/11/07 16:23:20]

Can you add a test for 

http://people.mozilla.org/~jorendorff/es6-draft.html#sec-string-literals-stat...

UnicodeEscapeSequence :: u{ HexDigits }

  It is a Syntax Error if the MV of HexDigits > 1114111.

[marja, 2014/11/13 11:53:20]

Done.

     NULL};
   RunParserSyncTest(context_data, data, kError);
 }
+
+
+TEST(UnicodeEscapes) {
+  const char* context_data[][2] = {{"", ""},
+                                   {"'use strict';", ""},
+                                   {NULL, NULL}};
+  const char* data[] = {
+    // Identifier starting with escape
+    "var \\u0052oo = 0;",
+    "var \\u{0052}oo = 0;",
+    // Identifier with an escape but not starting with an escape
+    "var foob\\uc481r = 0;",
+    "var foob\\u{c481}r = 0;",
+    // String with an escape
+    "\"foob\\uc481r\"",
+    "\"foob\\{uc481}r\"",
+    // Regexp body
+    "/(\\u0066|\\u0062)oo/",
+    "/(\\u{0066}|\\u{0062})oo/",
+    "/[\\u0062-\\u0066]oo/",
+    "/[\\u{0062}-\\u{0066}]oo/",
+    // If the { cannot be matched, the escape is only \u and the rest is
+    // not part of the escape.
+    "/(\\u{0066|\\u{0062)oo/",
+    "/[\\u{0062-\\u{0066 ]oo/",

[arv (Not doing code reviews), 2014/11/07 16:23:20]

Can you add a test with more than 4 hex numbers?

The following should be legal

\U{000000000000000000000000000000000000000000000000062}

[marja, 2014/11/13 11:53:20]

Done.

+    NULL};
+  RunParserSyncTest(context_data, data, kSuccess);
+}