Inline fast-path of Scope::LookupLocal

BUG=v8:5209

Review-Url: https://codereview.chromium.org/2275773002
Cr-Commit-Position: refs/heads/master@{#38865}

src/ast/scopes.cc

@@ -589,12 +589,7 @@ void Scope::PropagateUsageFlagsToScope(Scope* other) {
   if (calls_eval()) other->RecordEvalCall();
 }
 
-
-Variable* Scope::LookupLocal(const AstRawString* name) {
-  Variable* result = variables_.Lookup(name);
-  if (result != NULL || scope_info_.is_null()) {
-    return result;
-  }
+Variable* Scope::LookupInScopeInfo(const AstRawString* name) {
   Handle<String> name_handle = name->string();
   // The Scope is backed up by ScopeInfo. This means it cannot operate in a
   // heap-independent mode, and all strings must be internalized immediately. So

src/ast/scopes.h

@@ -120,7 +120,13 @@ class Scope: public ZoneObject {
   // Declarations
 
   // Lookup a variable in this scope. Returns the variable or NULL if not found.
-  Variable* LookupLocal(const AstRawString* name);
+  Variable* LookupLocal(const AstRawString* name) {
+    Variable* result = variables_.Lookup(name);
+    if (result != nullptr || scope_info_.is_null()) return result;
+    return LookupInScopeInfo(name);
+  }
+
+  Variable* LookupInScopeInfo(const AstRawString* name);
 
   // Lookup a variable in this scope or outer scopes.
   // Returns the variable or NULL if not found.