Remove funky 2-stage initialization of ParserInfo and an adventurous memset.

src/parser.h

Index: src/parser.h
diff --git a/src/parser.h b/src/parser.h
index 078383b391284425bd14dd37a0d8dee5fe879267..c73caae51b60a5dca2880773474eea9a5bbebf31 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -25,10 +25,10 @@ class Target;
 // A container for the inputs, configuration options, and outputs of parsing.
 class ParseInfo {
  public:
-  explicit ParseInfo(Zone* zone) {
-    memset(this, 0, sizeof(ParseInfo));
-    zone_ = zone;
-  }
+  explicit ParseInfo(Zone* zone);
+  ParseInfo(Zone* zone, Handle<JSFunction> function);
+  ParseInfo(Zone* zone, Handle<SharedFunctionInfo> shared);
+  ParseInfo(Zone* zone, Handle<Script> script);
 
   ~ParseInfo() {
     if (ast_value_factory_owned()) {
@@ -38,11 +38,6 @@ class ParseInfo {
     ast_value_factory_ = nullptr;
   }
 
-  ParseInfo* InitializeFromJSFunction(Handle<JSFunction> function);
-  ParseInfo* InitializeFromSharedFunctionInfo(
-      Handle<SharedFunctionInfo> shared);
-  ParseInfo* InitializeFromScript(Handle<Script> script);
-
   Zone* zone() { return zone_; }
 
 // Convenience accessor methods for flags.