[turbofan] Fix Projection operator parameter type.

src/compiler/node.cc

Index: src/compiler/node.cc
diff --git a/src/compiler/node.cc b/src/compiler/node.cc
index 66294bd180449b6a21e00e0aff88960e1a9886d9..7df736ee129471af9f291adf32d1163395e2c599 100644
--- a/src/compiler/node.cc
+++ b/src/compiler/node.cc
@@ -23,19 +23,18 @@ void Node::CollectProjections(NodeVector* projections) {
   }
   for (UseIter i = uses().begin(); i != uses().end(); ++i) {
     if ((*i)->opcode() != IrOpcode::kProjection) continue;
-    int32_t index = OpParameter<int32_t>(*i);
-    DCHECK_GE(index, 0);
-    DCHECK_LT(index, static_cast<int32_t>(projections->size()));
+    size_t index = OpParameter<size_t>(*i);
+    DCHECK_LT(index, projections->size());
     DCHECK_EQ(NULL, (*projections)[index]);
     (*projections)[index] = *i;
   }
 }
 
 
-Node* Node::FindProjection(int32_t projection_index) {
+Node* Node::FindProjection(size_t projection_index) {
   for (UseIter i = uses().begin(); i != uses().end(); ++i) {
     if ((*i)->opcode() == IrOpcode::kProjection &&
-        OpParameter<int32_t>(*i) == projection_index) {
+        OpParameter<size_t>(*i) == projection_index) {
       return *i;
     }
   }