Revert "Added ability to lock strings to prevent their representation or encoding from changing."

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 74fb01257954d77788f4e3cfa2bf16d478b0f1fa..7e531b28ae38ebbb5092934e196f483384cfddaf 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -5766,6 +5766,7 @@ class StringHasher {
   uint32_t raw_running_hash_;
   uint32_t array_index_;
   bool is_array_index_;
+  bool is_first_char_;
   bool is_valid_;
   friend class TwoCharHashTableKey;
 };
@@ -6217,25 +6218,15 @@ class SeqString: public String {
   // Layout description.
   static const int kHeaderSize = String::kSize;
 
-  // Shortcuts for templates that know their string-type exactly.
-  bool IsExternalAsciiString() {
-    return false;
-  }
-  bool IsExternalTwoByteString() {
-    return false;
-  }
-
-
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(SeqString);
 };
 
 
-// The SeqAsciiString class captures sequential ASCII string objects.
-// Each character in the AsciiString is an ASCII character.
+// The AsciiString class captures sequential ascii string objects.
+// Each character in the AsciiString is an ascii character.
 class SeqAsciiString: public SeqString {
  public:
-  typedef char CharType;
   static const bool kHasAsciiEncoding = true;
 
   // Dispatched behavior.
@@ -6250,15 +6241,6 @@ class SeqAsciiString: public SeqString {
   // Casting
   static inline SeqAsciiString* cast(Object* obj);
 
-  bool IsSeqAsciiString() {
-    ASSERT(this->Object::IsSeqAsciiString());
-    return true;
-  }
-  bool IsSeqTwoByteString() {
-    ASSERT(this->Object::IsSeqAsciiString());
-    return false;
-  }
-
   // Garbage collection support.  This method is called by the
   // garbage collector to compute the actual size of an AsciiString
   // instance.
@@ -6288,12 +6270,10 @@ class SeqAsciiString: public SeqString {
 };
 
 
-// The SeqTwoByteString class captures sequential unicode string objects.
+// The TwoByteString class captures sequential unicode string objects.
 // Each character in the TwoByteString is a two-byte uint16_t.
 class SeqTwoByteString: public SeqString {
  public:
-  typedef uc16 CharType;
-
   static const bool kHasAsciiEncoding = false;
 
   // Dispatched behavior.
@@ -6310,14 +6290,6 @@ class SeqTwoByteString: public SeqString {
 
   // Casting
   static inline SeqTwoByteString* cast(Object* obj);
-  bool IsSeqTwoByteString() {
-    ASSERT(this->Object::IsSeqTwoByteString());
-    return true;
-  }
-  bool IsSeqAsciiString() {
-    ASSERT(this->Object::IsSeqTwoByteString());
-    return false;
-  }
 
   // Garbage collection support.  This method is called by the
   // garbage collector to compute the actual size of a TwoByteString
@@ -6478,14 +6450,6 @@ class ExternalString: public String {
 
   STATIC_CHECK(kResourceOffset == Internals::kStringResourceOffset);
 
-  // Shortcuts for templates that know their string type exactly.
-  bool IsSeqAsciiString() {
-    return false;
-  }
-  bool IsSeqTwoByteString() {
-    return false;
-  }
-
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ExternalString);
 };
@@ -6495,8 +6459,6 @@ class ExternalString: public String {
 // ASCII string.
 class ExternalAsciiString: public ExternalString {
  public:
-  typedef char CharType;
-
   static const bool kHasAsciiEncoding = true;
 
   typedef v8::String::ExternalAsciiStringResource Resource;
@@ -6510,14 +6472,6 @@ class ExternalAsciiString: public ExternalString {
 
   // Casting.
   static inline ExternalAsciiString* cast(Object* obj);
-  bool IsExternalAsciiString() {
-    ASSERT(this->Object::IsExternalAsciiString());
-    return true;
-  }
-  bool IsExternalTwoByteString() {
-    ASSERT(this->Object::IsExternalAsciiString());
-    return false;
-  }
 
   // Garbage collection support.
   inline void ExternalAsciiStringIterateBody(ObjectVisitor* v);
@@ -6538,11 +6492,10 @@ class ExternalAsciiString: public ExternalString {
 };
 
 
-// The ExternalTwoByteString class is an external string backed by a 16-bit
-// character sequence.
+// The ExternalTwoByteString class is an external string backed by a UTF-16
+// encoded string.
 class ExternalTwoByteString: public ExternalString {
  public:
-  typedef uc16 CharType;
   static const bool kHasAsciiEncoding = false;
 
   typedef v8::String::ExternalStringResource Resource;
@@ -6559,14 +6512,6 @@ class ExternalTwoByteString: public ExternalString {
 
   // Casting.
   static inline ExternalTwoByteString* cast(Object* obj);
-  bool IsExternalTwoByteString() {
-    ASSERT(this->Object::IsExternalTwoByteString());
-    return true;
-  }
-  bool IsExternalAsciiString() {
-    ASSERT(this->Object::IsExternalTwoByteString());
-    return false;
-  }
 
   // Garbage collection support.
   inline void ExternalTwoByteStringIterateBody(ObjectVisitor* v);