[turbofan] Add new Float32Abs and Float64Abs operators.

src/compiler/common-operator-reducer.h

Index: src/compiler/common-operator-reducer.h
diff --git a/src/compiler/common-operator-reducer.h b/src/compiler/common-operator-reducer.h
index dfcbe295bc47ed9c0fb5361bb2bfdc9574f2bd5a..2a814a0bc767eea4290dd27a5f0c9cccf62d13dc 100644
--- a/src/compiler/common-operator-reducer.h
+++ b/src/compiler/common-operator-reducer.h
@@ -16,6 +16,7 @@ class CommonOperatorBuilder;
 class Graph;
 class JSGraph;
 class MachineOperatorBuilder;
+class Operator;
 
 
 // Performs strength reduction on nodes that have common operators.
@@ -31,6 +32,9 @@ class CommonOperatorReducer FINAL : public Reducer {
   Reduction ReducePhi(Node* node);
   Reduction ReduceSelect(Node* node);
 
+  Reduction Change(Node* node, Operator const* op, Node* a);
+  Reduction Change(Node* node, Operator const* op, Node* a, Node* b);
+
   CommonOperatorBuilder* common() const;
   Graph* graph() const;
   JSGraph* jsgraph() const { return jsgraph_; }