[Isolates] Merge crankshaft (r5922 from bleeding_edge).

src/x64/frames-x64.h

Index: src/x64/frames-x64.h
diff --git a/src/x64/frames-x64.h b/src/x64/frames-x64.h
index b90557ed63a7dc2aec367bcf66027b2bed3b83c7..7227e2494f9ae2098d3938260afec60409b634a9 100644
--- a/src/x64/frames-x64.h
+++ b/src/x64/frames-x64.h
@@ -45,6 +45,12 @@ static const int kNumJSCallerSaved = 5;
 
 typedef Object* JSCallerSavedBuffer[kNumJSCallerSaved];
 
+// Number of registers for which space is reserved in safepoints.
+// TODO(x64): This should not be 0.
+static const int kNumSafepointRegisters = 0;
+
+// ----------------------------------------------------
+
 class StackHandlerConstants : public AllStatic {
  public:
   static const int kNextOffset  = 0 * kPointerSize;