Pseudo element selectors in compound selector lists are invalid.

third_party/WebKit/Source/core/css/parser/CSSSelectorParserTest.cpp

Index: third_party/WebKit/Source/core/css/parser/CSSSelectorParserTest.cpp
diff --git a/third_party/WebKit/Source/core/css/parser/CSSSelectorParserTest.cpp b/third_party/WebKit/Source/core/css/parser/CSSSelectorParserTest.cpp
index 6596b8441ca4d28dc81146aca2720487281ee0b5..8de24d4839410fc733f8f9e841e9abd5f1a22a20 100644
--- a/third_party/WebKit/Source/core/css/parser/CSSSelectorParserTest.cpp
+++ b/third_party/WebKit/Source/core/css/parser/CSSSelectorParserTest.cpp
@@ -133,4 +133,29 @@ TEST(CSSSelectorParserTest, ShadowDomPseudoInCompound)
     }
 }
 
+TEST(CSSSelectorParserTest, PseudoElementsInCompoundLists)
+{
+    const char* testCases[] = {
+        ":not(::before)",
+        ":not(::content)",
+        ":not(::shadow)",
+        ":host(::before)",
+        ":host(::content)",
+        ":host(::shadow)",
+        ":host-context(::before)",
+        ":host-context(::content)",
+        ":host-context(::shadow)",
+        ":-webkit-any(::after, ::before)",
+        ":-webkit-any(::content, span)",
+        ":-webkit-any(div, ::shadow)"
+    };
+
+    for (auto testCase : testCases) {
+        CSSTokenizer::Scope scope(testCase);
+        CSSParserTokenRange range = scope.tokenRange();
+        CSSSelectorList list = CSSSelectorParser::parseSelector(range, CSSParserContext(HTMLStandardMode, nullptr), nullptr);
+        EXPECT_FALSE(list.isValid());
+    }
+}
+
 } // namespace