[turbofan] Optimize certain chains of Branch into a Switch.

src/compiler/instruction-selector.h

Index: src/compiler/instruction-selector.h
diff --git a/src/compiler/instruction-selector.h b/src/compiler/instruction-selector.h
index 3883b1556a2602c0fb4569c86f39b3407923e803..5c31db74e9a158dd495283fbfe3f119768850530 100644
--- a/src/compiler/instruction-selector.h
+++ b/src/compiler/instruction-selector.h
@@ -202,7 +202,9 @@ class InstructionSelector FINAL {
   void VisitCall(Node* call);
   void VisitGoto(BasicBlock* target);
   void VisitBranch(Node* input, BasicBlock* tbranch, BasicBlock* fbranch);
-  void VisitSwitch(Node* node, BasicBlock** branches, size_t branch_count);
+  void VisitSwitch(Node* node, BasicBlock* default_branch,
+                   BasicBlock** case_branches, int32_t* case_values,
+                   size_t case_count, int32_t min_value, int32_t max_value);
   void VisitReturn(Node* value);
   void VisitThrow(Node* value);
   void VisitDeoptimize(Node* deopt);