Unify memory optimization modes and flags.

src/isolate.h

 // Copyright 2012 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_ISOLATE_H_
 #define V8_ISOLATE_H_
 
 #include <memory>
 #include <queue>
 #include <set>
@@ skipping 1144 matching lines @@
   }
 
   interpreter::Interpreter* interpreter() const { return interpreter_; }
 
   base::AccountingAllocator* allocator() { return allocator_; }
 
   bool IsInAnyContext(Object* object, uint32_t index);
 
   void SetRAILMode(RAILMode rail_mode);
 
+  void IsolateInForegroundNotification();
+
+  void IsolateInBackgroundNotification();
+
+  bool IsIsolateInBackground() { return is_isolate_in_background_; }
+
  protected:
   explicit Isolate(bool enable_serializer);
   bool IsArrayOrObjectPrototype(Object* object);
 
  private:
   friend struct GlobalState;
   friend struct InitializeGlobalState;
   Handle<JSObject> SetUpSubregistry(Handle<JSObject> registry, Handle<Map> map,
                                     const char* name);
 
@@ skipping 171 matching lines @@
 
   // True if fatal error has been signaled for this isolate.
   bool has_fatal_error_;
 
   // True if this isolate was initialized from a snapshot.
   bool initialized_from_snapshot_;
 
   // True if ES2015 tail call elimination feature is enabled.
   bool is_tail_call_elimination_enabled_;
 
+  // True if the isolate is in background. This flag is used
+  // to prioritize between memory usage and latency.
+  bool is_isolate_in_background_;
+
   // Time stamp at initialization.
   double time_millis_at_init_;
 
 #ifdef DEBUG
   // A static array of histogram info for each type.
   HistogramInfo heap_histograms_[LAST_TYPE + 1];
   JSObject::SpillInformation js_spill_information_;
 #endif
 
   Debug* debug_;
@@ skipping 301 matching lines @@
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ISOLATE_H_