Introduce LanguageMode, drop StrictMode.

src/full-codegen.h

 // Copyright 2012 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_FULL_CODEGEN_H_
 #define V8_FULL_CODEGEN_H_
 
 #include "src/v8.h"
 
 #include "src/allocation.h"
@@ skipping 585 matching lines @@
                              Expression* left,
                              Expression* right);
 
   // Assign to the given expression as if via '='. The right-hand-side value
   // is expected in the accumulator.
   void EmitAssignment(Expression* expr);
 
   // Shall an error be thrown if assignment with 'op' operation is perfomed
   // on this variable in given language mode?
   static bool IsSignallingAssignmentToConst(Variable* var, Token::Value op,
-                                            StrictMode strict_mode) {
+                                            LanguageMode language_mode) {
     if (var->mode() == CONST) return op != Token::INIT_CONST;
 
     if (var->mode() == CONST_LEGACY) {
-      return strict_mode == STRICT && op != Token::INIT_CONST_LEGACY;
+      return is_strict(language_mode) && op != Token::INIT_CONST_LEGACY;
     }
 
     return false;
   }
 
   // Complete a variable assignment.  The right-hand-side value is expected
   // in the accumulator.
   void EmitVariableAssignment(Variable* var,
                               Token::Value op);
 
@@ skipping 58 matching lines @@
 
   MacroAssembler* masm() { return masm_; }
 
   class ExpressionContext;
   const ExpressionContext* context() { return context_; }
   void set_new_context(const ExpressionContext* context) { context_ = context; }
 
   Handle<Script> script() { return info_->script(); }
   bool is_eval() { return info_->is_eval(); }
   bool is_native() { return info_->is_native(); }
-  StrictMode strict_mode() { return function()->strict_mode(); }
+  LanguageMode language_mode() { return function()->language_mode(); }
   FunctionLiteral* function() { return info_->function(); }
   Scope* scope() { return scope_; }
 
   static Register result_register();
   static Register context_register();
 
   // Set fields in the stack frame. Offsets are the frame pointer relative
   // offsets defined in, e.g., StandardFrameConstants.
   void StoreToFrameField(int frame_offset, Register value);
 
@@ skipping 350 matching lines @@
 
   Address start_;
   Address instruction_start_;
   uint32_t length_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_FULL_CODEGEN_H_