Introduce LanguageMode, drop StrictMode.

src/contexts.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_CONTEXTS_H_
 #define V8_CONTEXTS_H_
 
 #include "src/heap/heap.h"
 #include "src/objects.h"
 
@@ skipping 554 matching lines @@
                         ContextLookupFlags flags,
                         int* index,
                         PropertyAttributes* attributes,
                         BindingFlags* binding_flags);
 
   // Code generation support.
   static int SlotOffset(int index) {
     return kHeaderSize + index * kPointerSize - kHeapObjectTag;
   }
 
-  static int FunctionMapIndex(StrictMode strict_mode, FunctionKind kind) {
+  static int FunctionMapIndex(LanguageMode language_mode, FunctionKind kind) {
     if (IsGeneratorFunction(kind)) {
-      return strict_mode == SLOPPY ? SLOPPY_GENERATOR_FUNCTION_MAP_INDEX
-                                   : STRICT_GENERATOR_FUNCTION_MAP_INDEX;
+      return is_strict(language_mode) ? STRICT_GENERATOR_FUNCTION_MAP_INDEX
+                                      : SLOPPY_GENERATOR_FUNCTION_MAP_INDEX;
     }
 
     if (IsArrowFunction(kind) || IsConciseMethod(kind)) {
-      return strict_mode == SLOPPY
-                 ? SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX
-                 : STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX;
+      return is_strict(language_mode)
+                 ? STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX
+                 : SLOPPY_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX;
     }
 
-    return strict_mode == SLOPPY ? SLOPPY_FUNCTION_MAP_INDEX
-                                 : STRICT_FUNCTION_MAP_INDEX;
+    return is_strict(language_mode) ? STRICT_FUNCTION_MAP_INDEX
+                                    : SLOPPY_FUNCTION_MAP_INDEX;
   }
 
   static const int kSize = kHeaderSize + NATIVE_CONTEXT_SLOTS * kPointerSize;
 
   // GC support.
   typedef FixedBodyDescriptor<
       kHeaderSize, kSize, kSize> ScavengeBodyDescriptor;
 
   typedef FixedBodyDescriptor<
       kHeaderSize,
@@ skipping 10 matching lines @@
   static bool IsBootstrappingOrGlobalObject(Isolate* isolate, Object* object);
 #endif
 
   STATIC_ASSERT(kHeaderSize == Internals::kContextHeaderSize);
   STATIC_ASSERT(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CONTEXTS_H_