Do not count invocations but usage of a function, i.e., increment a function's counter at IC calls …

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 4582)
+++ runtime/vm/object.h	(working copy)
@@ -1336,14 +1336,14 @@
   }
   void set_num_optional_parameters(intptr_t value) const;
 
-  static intptr_t invocation_counter_offset() {
-    return OFFSET_OF(RawFunction, invocation_counter_);
+  static intptr_t usage_counter_offset() {
+    return OFFSET_OF(RawFunction, usage_counter_);
   }
-  intptr_t invocation_counter() const {
-    return raw_ptr()->invocation_counter_;
+  intptr_t usage_counter() const {
+    return raw_ptr()->usage_counter_;
   }
-  void set_invocation_counter(intptr_t value) const {
-    raw_ptr()->invocation_counter_ = value;
+  void set_usage_counter(intptr_t value) const {
+    raw_ptr()->usage_counter_ = value;
   }
 
   intptr_t deoptimization_counter() const {
@@ -3654,6 +3654,10 @@
     return OFFSET_OF(RawICData, ic_data_);
   }
 
+  static intptr_t function_offset() {
+    return OFFSET_OF(RawICData, function_);
+  }
+
   void AddCheck(const GrowableArray<const Class*>& classes,
                 const Function& target) const;
   void GetCheckAt(intptr_t index,