[turbofan] Introduce dedicated CallFrequency class.

src/compiler/js-inlining-heuristic.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_JS_INLINING_HEURISTIC_H_
 #define V8_COMPILER_JS_INLINING_HEURISTIC_H_
 
 #include "src/compiler/js-inlining.h"
 
 namespace v8 {
@@ skipping 25 matching lines @@
   static const int kMaxCallPolymorphism = 4;
 
   struct Candidate {
     Handle<JSFunction> functions[kMaxCallPolymorphism];
     // TODO(2206): For now polymorphic inlining is treated orthogonally to
     // inlining based on SharedFunctionInfo. This should be unified and the
     // above array should be switched to SharedFunctionInfo instead. Currently
     // we use {num_functions == 1 && functions[0].is_null()} as an indicator.
     Handle<SharedFunctionInfo> shared_info;
     int num_functions;
-    Node* node = nullptr;    // The call site at which to inline.
-    float frequency = 0.0f;  // Relative frequency of this call site.
+    Node* node = nullptr;     // The call site at which to inline.
+    CallFrequency frequency;  // Relative frequency of this call site.
   };
 
   // Comparator for candidates.
   struct CandidateCompare {
     bool operator()(const Candidate& left, const Candidate& right) const;
   };
 
   // Candidates are kept in a sorted set of unique candidates.
   typedef ZoneSet<Candidate, CandidateCompare> Candidates;
 
@@ skipping 12 matching lines @@
   ZoneSet<NodeId> seen_;
   JSGraph* const jsgraph_;
   int cumulative_count_ = 0;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_JS_INLINING_HEURISTIC_H_