Update V8 to r6101 as required by WebKit r74534

Change-Id: I7f84af8dd732f11898fd644b2c2b1538914cb78d
diff --git a/src/data-flow.cc b/src/data-flow.cc
index be82446..9c02ff4 100644
--- a/src/data-flow.cc
+++ b/src/data-flow.cc
@@ -33,7 +33,6 @@
 namespace v8 {
 namespace internal {
 
-
 #ifdef DEBUG
 void BitVector::Print() {
   bool first = true;
@@ -50,13 +49,39 @@
 #endif
 
 
+void BitVector::Iterator::Advance() {
+  current_++;
+  uint32_t val = current_value_;
+  while (val == 0) {
+    current_index_++;
+    if (Done()) return;
+    val = target_->data_[current_index_];
+    current_ = current_index_ << 5;
+  }
+  val = SkipZeroBytes(val);
+  val = SkipZeroBits(val);
+  current_value_ = val >> 1;
+}
+
+
 bool AssignedVariablesAnalyzer::Analyze(CompilationInfo* info) {
-  info_ = info;
   Scope* scope = info->scope();
-  int variables = scope->num_parameters() + scope->num_stack_slots();
-  if (variables == 0) return true;
-  av_.ExpandTo(variables);
-  VisitStatements(info->function()->body());
+  int size = scope->num_parameters() + scope->num_stack_slots();
+  if (size == 0) return true;
+  AssignedVariablesAnalyzer analyzer(info, size);
+  return analyzer.Analyze();
+}
+
+
+AssignedVariablesAnalyzer::AssignedVariablesAnalyzer(CompilationInfo* info,
+                                                     int size)
+    : info_(info), av_(size) {
+}
+
+
+bool AssignedVariablesAnalyzer::Analyze() {
+  ASSERT(av_.length() > 0);
+  VisitStatements(info_->function()->body());
   return !HasStackOverflow();
 }
 
@@ -318,11 +343,6 @@
 }
 
 
-void AssignedVariablesAnalyzer::VisitSlot(Slot* expr) {
-  UNREACHABLE();
-}
-
-
 void AssignedVariablesAnalyzer::VisitVariableProxy(VariableProxy* expr) {
   // Nothing to do.
   ASSERT(av_.IsEmpty());