Recognize HTMLCloseComment after multiline comment

When the scanner finds a '-->', it's either part of an HTMLCloseComment
or a '--' followed by a '>'. Previously, only a preceding newline would
make it an HTMLCloseComment. Now, a preceding multiline comment also
makes it an HTMLCloseComment. The effect is that now the following is
not a SyntaxError:

x/*
*/-->this is now a comment

BUG=v8:5142
LOG=y

Review-Url: https://codereview.chromium.org/2119763003
Cr-Commit-Position: refs/heads/master@{#37656}

src/parsing/scanner.cc

@@ -564,7 +564,7 @@ void Scanner::Scan() {
         Advance();
         if (c0_ == '-') {
           Advance();
-          if (c0_ == '>' && has_line_terminator_before_next_) {
+          if (c0_ == '>' && HasAnyLineTerminatorBeforeNext()) {
             // For compatibility with SpiderMonkey, we skip lines that
             // start with an HTML comment end '-->'.
             token = SkipSingleLineComment();

test/cctest/test-parsing.cc

@@ -120,15 +120,32 @@ TEST(ScanHTMLEndComments) {
   // whitespace, even a multiline-comment containing a newline).
   // This was not the case if it occurred before the first real token
   // in the input.
+  // clang-format off
   const char* tests[] = {
       // Before first real token.
+      "-->",
+      "--> is eol-comment",
       "--> is eol-comment\nvar y = 37;\n",
       "\n --> is eol-comment\nvar y = 37;\n",
+      "\n-->is eol-comment\nvar y = 37;\n",
+      "\n-->\nvar y = 37;\n",
       "/* precomment */ --> is eol-comment\nvar y = 37;\n",
+      "/* precomment */-->eol-comment\nvar y = 37;\n",
       "\n/* precomment */ --> is eol-comment\nvar y = 37;\n",
+      "\n/*precomment*/-->eol-comment\nvar y = 37;\n",
       // After first real token.
       "var x = 42;\n--> is eol-comment\nvar y = 37;\n",
       "var x = 42;\n/* precomment */ --> is eol-comment\nvar y = 37;\n",
+      "x/* precomment\n */ --> is eol-comment\nvar y = 37;\n",
+      "var x = 42; /* precomment\n */ --> is eol-comment\nvar y = 37;\n",
+      "var x = 42;/*\n*/-->is eol-comment\nvar y = 37;\n",
+      // With multiple comments preceding HTMLEndComment
+      "/* MLC \n */ /* SLDC */ --> is eol-comment\nvar y = 37;\n",
+      "/* MLC \n */ /* SLDC1 */ /* SLDC2 */ --> is eol-comment\nvar y = 37;\n",
+      "/* MLC1 \n */ /* MLC2 \n */ --> is eol-comment\nvar y = 37;\n",
+      "/* SLDC */ /* MLC \n */ --> is eol-comment\nvar y = 37;\n",
+      "/* MLC1 \n */ /* SLDC1 */ /* MLC2 \n */ /* SLDC2 */ --> is eol-comment\n"
+          "var y = 37;\n",
       NULL
   };
 
@@ -136,11 +153,10 @@ TEST(ScanHTMLEndComments) {
       "x --> is eol-comment\nvar y = 37;\n",
       "\"\\n\" --> is eol-comment\nvar y = 37;\n",
       "x/* precomment */ --> is eol-comment\nvar y = 37;\n",
-      "x/* precomment\n */ --> is eol-comment\nvar y = 37;\n",
       "var x = 42; --> is eol-comment\nvar y = 37;\n",
-      "var x = 42; /* precomment\n */ --> is eol-comment\nvar y = 37;\n",
       NULL
   };
+  // clang-format on
 
   // Parser/Scanner needs a stack limit.
   CcTest::i_isolate()->stack_guard()->SetStackLimit(

test/webkit/parser-xml-close-comment-expected.txt

@@ -30,7 +30,7 @@ PASS 'should be a syntax error' --> threw exception ReferenceError: Invalid left
 PASS /**/ 1 --> threw exception ReferenceError: Invalid left-hand side expression in postfix operation.
 PASS 1 /**/ --> threw exception ReferenceError: Invalid left-hand side expression in postfix operation.
 PASS 1/*
-*/--> threw exception SyntaxError: Unexpected token >.
+*/--> is 1
 PASS --> is undefined.
 PASS /**/--> is undefined.
 PASS /*

test/webkit/parser-xml-close-comment.js

@@ -26,7 +26,7 @@ description("Test to ensure correct handling of --> as a single line comment whe
 shouldThrow("'should be a syntax error' -->");
 shouldThrow("/**/ 1 -->");
 shouldThrow("1 /**/ -->");
-shouldThrow("1/*\n*/-->");
+shouldBe("1/*\n*/-->", "1");
 
 shouldBeUndefined("-->");
 shouldBeUndefined("/**/-->");