Reland "Add initial support for inlining."

src/compiler/js-inlining.h

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_COMPILER_JS_INLINING_H_
+#define V8_COMPILER_JS_INLINING_H_
+
+#include "src/compiler/js-graph.h"
+#include "src/v8.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+class JSInliner {
+ public:
+  JSInliner(CompilationInfo* info, JSGraph* jsgraph)
+      : info_(info), jsgraph_(jsgraph) {}
+
+  void Inline();
+  void TryInlineCall(Node* node);
+
+ private:
+  friend class InlinerVisitor;
+  CompilationInfo* info_;
+  JSGraph* jsgraph_;
+
+  static void UnifyReturn(Graph* graph);
+};
+}
+}
+}  // namespace v8::internal::compiler
+
+#endif  // V8_COMPILER_JS_INLINING_H_