[compiler] Remove dangerous language mode accessors.

src/crankshaft/ppc/lithium-codegen-ppc.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_CRANKSHAFT_PPC_LITHIUM_CODEGEN_PPC_H_
 #define V8_CRANKSHAFT_PPC_LITHIUM_CODEGEN_PPC_H_
 
 #include "src/ast/scopes.h"
 #include "src/crankshaft/lithium-codegen.h"
 #include "src/crankshaft/ppc/lithium-gap-resolver-ppc.h"
@@ skipping 110 matching lines @@
 
   // Emit frame translation commands for an environment.
   void WriteTranslation(LEnvironment* environment, Translation* translation);
 
 // Declare methods that deal with the individual node types.
 #define DECLARE_DO(type) void Do##type(L##type* node);
   LITHIUM_CONCRETE_INSTRUCTION_LIST(DECLARE_DO)
 #undef DECLARE_DO
 
  private:
-  LanguageMode language_mode() const { return info()->language_mode(); }
-
   Scope* scope() const { return scope_; }
 
   Register scratch0() { return kLithiumScratch; }
   DoubleRegister double_scratch0() { return kScratchDoubleReg; }
 
   LInstruction* GetNextInstruction();
 
   void EmitClassOfTest(Label* if_true, Label* if_false,
                        Handle<String> class_name, Register input,
                        Register temporary, Register temporary2);
@@ skipping 210 matching lines @@
   LCodeGen* codegen_;
   Label entry_;
   Label exit_;
   Label* external_exit_;
   int instruction_index_;
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CRANKSHAFT_PPC_LITHIUM_CODEGEN_PPC_H_