[heap] Introduce enum of garbage collection reasons.

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 107 matching lines @@
     if (!initialize_called_) InitializeVM();
     return i_isolate();
   }
 
   static i::Isolate* i_isolate() {
     return reinterpret_cast<i::Isolate*>(isolate());
   }
 
   static i::Heap* heap();
 
+  static void CollectGarbage(i::AllocationSpace space);
+  static void CollectAllGarbage(int flags);
+  static void CollectAllAvailableGarbage();
+
   static v8::base::RandomNumberGenerator* random_number_generator();
 
   static v8::Local<v8::Object> global();
 
   static v8::ArrayBuffer::Allocator* array_buffer_allocator() {
     return allocator_;
   }
 
   static void set_array_buffer_allocator(
       v8::ArrayBuffer::Allocator* allocator) {
@@ skipping 443 matching lines @@
 
   // Prefixing the below with main_ reduces a lot of naming clashes.
   i::Zone* main_zone() { return main_zone_.get(); }
 
  private:
   v8::base::AccountingAllocator allocator_;
   std::unique_ptr<i::Zone> main_zone_;
 };
 
 #endif  // ifndef CCTEST_H_