Revert of Internalize strings in-place

src/objects-debug.cc

 // 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.
 
 #include "src/objects.h"
 
 #include "src/bootstrapper.h"
 #include "src/disasm.h"
 #include "src/disassembler.h"
 #include "src/field-type.h"
@@ skipping 537 matching lines @@
 void String::StringVerify() {
   CHECK(IsString());
   CHECK(length() >= 0 && length() <= Smi::kMaxValue);
   if (IsInternalizedString()) {
     CHECK(!GetHeap()->InNewSpace(this));
   }
   if (IsConsString()) {
     ConsString::cast(this)->ConsStringVerify();
   } else if (IsSlicedString()) {
     SlicedString::cast(this)->SlicedStringVerify();
-  } else if (IsThinString()) {
-    ThinString::cast(this)->ThinStringVerify();
   }
 }
 
 
 void ConsString::ConsStringVerify() {
   CHECK(this->first()->IsString());
   CHECK(this->second() == GetHeap()->empty_string() ||
         this->second()->IsString());
   CHECK(this->length() >= ConsString::kMinLength);
   CHECK(this->length() == this->first()->length() + this->second()->length());
   if (this->IsFlat()) {
-    // A flat cons can only be created by String::SlowFlatten.
-    // Afterwards, the first part may be externalized or internalized.
-    CHECK(this->first()->IsSeqString() || this->first()->IsExternalString() ||
-          this->first()->IsThinString());
+    // A flat cons can only be created by String::SlowTryFlatten.
+    // Afterwards, the first part may be externalized.
+    CHECK(this->first()->IsSeqString() || this->first()->IsExternalString());
   }
 }
 
-void ThinString::ThinStringVerify() {
-  CHECK(this->actual()->IsInternalizedString());
-  CHECK(this->actual()->IsSeqString() || this->actual()->IsExternalString());
-}
 
 void SlicedString::SlicedStringVerify() {
   CHECK(!this->parent()->IsConsString());
   CHECK(!this->parent()->IsSlicedString());
   CHECK(this->length() >= SlicedString::kMinLength);
 }
 
 
 void JSBoundFunction::JSBoundFunctionVerify() {
   CHECK(IsJSBoundFunction());
@@ skipping 970 matching lines @@
 
   // Both are done at the same time.
   CHECK_EQ(new_it.done(), old_it.done());
 }
 
 
 #endif  // DEBUG
 
 }  // namespace internal
 }  // namespace v8