Inline Declaration::IsInlineable into crankshaft

Those virtual methods shouldn't live on the AST since they are crankshaft specific, and can easily be checked inline.

BUG=

Review-Url: https://codereview.chromium.org/2125933004
Cr-Commit-Position: refs/heads/master@{#37572}

src/ast/ast.cc

@@ -712,18 +712,6 @@ bool CompareOperation::IsLiteralCompareNull(Expression** expr) {
 }
 
 
-// ----------------------------------------------------------------------------
-// Inlining support
-
-bool Declaration::IsInlineable() const {
-  return proxy()->var()->IsStackAllocated();
-}
-
-bool FunctionDeclaration::IsInlineable() const {
-  return false;
-}
-
-
 // ----------------------------------------------------------------------------
 // Recording of type feedback
 

src/ast/ast.h

@@ -512,7 +512,6 @@ class Declaration : public AstNode {
   VariableMode mode() const { return mode_; }
   Scope* scope() const { return scope_; }
   virtual InitializationFlag initialization() const = 0;
-  virtual bool IsInlineable() const;
 
  protected:
   Declaration(Zone* zone, VariableProxy* proxy, VariableMode mode, Scope* scope,
@@ -554,7 +553,6 @@ class FunctionDeclaration final : public Declaration {
   InitializationFlag initialization() const override {
     return kCreatedInitialized;
   }
-  bool IsInlineable() const override;
 
  protected:
   FunctionDeclaration(Zone* zone,

src/crankshaft/hydrogen.cc

@@ -8426,7 +8426,8 @@ bool HOptimizedGraphBuilder::TryInline(Handle<JSFunction> target,
   ZoneList<Declaration*>* decls = target_info.scope()->declarations();
   int decl_count = decls->length();
   for (int i = 0; i < decl_count; ++i) {
-    if (!decls->at(i)->IsInlineable()) {
+    if (decls->at(i)->IsFunctionDeclaration() ||
+        !decls->at(i)->proxy()->var()->IsStackAllocated()) {
       TraceInline(target, caller, "target has non-trivial declaration");
       return false;
     }