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_CONTEXT_SPECIALIZATION_H_
-#define V8_COMPILER_JS_CONTEXT_SPECIALIZATION_H_
+#ifndef V8_COMPILER_JS_INLINING_H_
+#define V8_COMPILER_JS_INLINING_H_
 
 #include "src/compiler/graph-reducer.h"
 #include "src/compiler/js-graph.h"
 #include "src/contexts.h"
 #include "src/v8.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
-// Specializes a given JSGraph to a given context, potentially constant folding
-// some {LoadContext} nodes or strength reducing some {StoreContext} nodes.
-class JSContextSpecializer {
+class JSInliner {
  public:
-  JSContextSpecializer(CompilationInfo* info, JSGraph* jsgraph, Node* context)
+  JSInliner(CompilationInfo* info, JSGraph* jsgraph, Node* context)
       : info_(info), jsgraph_(jsgraph), context_(context) {}
 
-  void SpecializeToContext();
-  Reduction ReduceJSLoadContext(Node* node);
-  Reduction ReduceJSStoreContext(Node* node);
+  void Inline();
 
  private:
+  friend class InlinerVisitor;
   CompilationInfo* info_;
   JSGraph* jsgraph_;
   Node* context_;
+
+  void InlineCall(Node* node);
+  static void UnifyReturn(JSGraph* graph);
 };
 }
 }
 }  // namespace v8::internal::compiler
 
-#endif  // V8_COMPILER_JS_CONTEXT_SPECIALIZATION_H_
+#endif  // V8_COMPILER_JS_INLINING_H_