Add support for IncrementCounter in Hydrogen.

src/x64/lithium-x64.h

Index: src/x64/lithium-x64.h
diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
index 50e32d8cd61ee999fd915aed6ddd4dc3ce0b3d07..4aa15347a600fdc80e2b76e3cc3206d8d9b45d9e 100644
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -79,6 +79,7 @@ class LCodeGen;
   V(CmpMapAndBranch)                            \
   V(CmpT)                                       \
   V(ConstantD)                                  \
+  V(ConstantE)                                  \
   V(ConstantI)                                  \
   V(ConstantS)                                  \
   V(ConstantT)                                  \
@@ -1166,6 +1167,17 @@ class LConstantD: public LTemplateInstruction<1, 0, 1> {
 };
 
 
+class LConstantE: public LTemplateInstruction<1, 0, 0> {
+ public:
+  DECLARE_CONCRETE_INSTRUCTION(ConstantE, "constant-e")
+  DECLARE_HYDROGEN_ACCESSOR(Constant)
+
+  ExternalReference value() const {
+    return hydrogen()->ExternalReferenceValue();
+  }
+};
+
+
 class LConstantT: public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantT, "constant-t")