Add the rate of js invocations from the api as a signal of idleness

test/cctest/cctest.h

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 512 matching lines @@
   v8::Local<v8::Value> result = CompileRun(code);
   CHECK(result->IsUndefined());
 }
 
 
 static inline void DisableInlineAllocationSteps(v8::internal::NewSpace* space) {
   space->LowerInlineAllocationLimit(0);
 }
 
 
+static inline void CheckDoubleEquals(double expected, double actual) {
+  const double kEpsilon = 1e-10;
+  CHECK_LE(expected, actual + kEpsilon);
+  CHECK_GE(expected, actual - kEpsilon);
+}
+
+
 static int LenFromSize(int size) {
   return (size - i::FixedArray::kHeaderSize) / i::kPointerSize;
 }
 
 
 static inline void CreatePadding(i::Heap* heap, int padding_size,
                                  i::PretenureFlag tenure) {
   const int max_number_of_objects = 20;
   v8::internal::Handle<v8::internal::FixedArray>
       big_objects[max_number_of_objects];
@@ skipping 144 matching lines @@
   HandleAndZoneScope() {}
 
   // Prefixing the below with main_ reduces a lot of naming clashes.
   i::Zone* main_zone() { return &main_zone_; }
 
  private:
   i::Zone main_zone_;
 };
 
 #endif  // ifndef CCTEST_H_