Revert workaround for http://crbug.com/9746.

src/objects.cc

Index: src/objects.cc
===================================================================
--- src/objects.cc	(revision 1858)
+++ src/objects.cc	(working copy)
@@ -3305,13 +3305,6 @@
   }
   ASSERT(string_tag == kExternalStringTag);
   ExternalTwoByteString* ext = ExternalTwoByteString::cast(string);
-  // This is a workaround for Chromium bug 9746: http://crbug.com/9746
-  // For external strings with a deleted resource we return a special
-  // Vector which will not compare to any string when doing SymbolTable
-  // lookups.
-  if (ext->resource() == NULL) {
-    return Vector<const uc16>(NULL, length);
-  }
   const uc16* start =
       reinterpret_cast<const uc16*>(ext->resource()->data());
   return Vector<const uc16>(start + offset, length);
@@ -4128,18 +4121,6 @@
 }
 
 
-// This is a workaround for Chromium bug 9746: http://crbug.com/9746
-// Returns true if this Vector matches the problem exposed in the bug.
-template <typename T>
-static bool CheckVectorForBug9746(Vector<T> vec) {
-  // The problem is that somehow external string entries in the symbol
-  // table can have their resources collected while they are still in the
-  // table. This should not happen according to the test in the function
-  // DisposeExternalString in api.cc, but we have evidence that it does.
-  return (vec.start() == NULL) ? true : false;
-}
-
-
 static StringInputBuffer string_compare_buffer_b;
 
 
@@ -4150,9 +4131,7 @@
       VectorIterator<char> ib(b->ToAsciiVector());
       return CompareStringContents(ia, &ib);
     } else {
-      Vector<const uc16> vb = b->ToUC16Vector();
-      if (CheckVectorForBug9746(vb)) return false;
-      VectorIterator<uc16> ib(vb);
+      VectorIterator<uc16> ib(b->ToUC16Vector());
       return CompareStringContents(ia, &ib);
     }
   } else {
@@ -4194,9 +4173,7 @@
           return CompareRawStringContents(vec1, vec2);
         } else {
           VectorIterator<char> buf1(vec1);
-          Vector<const uc16> vec2 = other->ToUC16Vector();
-          if (CheckVectorForBug9746(vec2)) return false;
-          VectorIterator<uc16> ib(vec2);
+          VectorIterator<uc16> ib(other->ToUC16Vector());
           return CompareStringContents(&buf1, &ib);
         }
       } else {
@@ -4206,15 +4183,13 @@
       }
     } else {
       Vector<const uc16> vec1 = this->ToUC16Vector();
-      if (CheckVectorForBug9746(vec1)) return false;
       if (other->IsFlat()) {
         if (other->IsAsciiRepresentation()) {
           VectorIterator<uc16> buf1(vec1);
           VectorIterator<char> ib(other->ToAsciiVector());
           return CompareStringContents(&buf1, &ib);
         } else {
-          Vector<const uc16> vec2 = other->ToUC16Vector();
-          if (CheckVectorForBug9746(vec2)) return false;
+          Vector<const uc16> vec2(other->ToUC16Vector());
           return CompareRawStringContents(vec1, vec2);
         }
       } else {
@@ -4259,18 +4234,6 @@
 
 
 bool String::IsEqualTo(Vector<const char> str) {
-  // This is a workaround for Chromium bug 9746: http://crbug.com/9746
-  // The problem is that somehow external string entries in the symbol
-  // table can have their resources deleted while they are still in the
-  // table. This should not happen according to the test in the function
-  // DisposeExternalString in api.cc but we have evidence that it does.
-  // Thus we add this bailout here.
-  StringShape shape(this);
-  if (shape.IsExternalTwoByte()) {
-    ExternalTwoByteString* ext = ExternalTwoByteString::cast(this);
-    if (ext->resource() == NULL) return false;
-  }
-
   int slen = length();
   Access<Scanner::Utf8Decoder> decoder(Scanner::utf8_decoder());
   decoder->Reset(str.start(), str.length());