[heap] Introduce enum of garbage collection reasons.

src/runtime/runtime-debug.cc

 // Copyright 2014 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.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/debug/debug-evaluate.h"
 #include "src/debug/debug-frames.h"
 #include "src/debug/debug-scopes.h"
@@ skipping 1504 matching lines @@
   context->set_security_token(isolate->native_context()->security_token());
   return context->global_proxy();
 }
 
 
 // Performs a GC.
 // Presently, it only does a full GC.
 RUNTIME_FUNCTION(Runtime_CollectGarbage) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
-  isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags, "%CollectGarbage");
+  isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
+                                     GarbageCollectionReason::kRuntime);
   return isolate->heap()->undefined_value();
 }
 
 
 // Gets the current heap usage.
 RUNTIME_FUNCTION(Runtime_GetHeapUsage) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 0);
   int usage = static_cast<int>(isolate->heap()->SizeOfObjects());
   if (!Smi::IsValid(usage)) {
@@ skipping 330 matching lines @@
   Handle<Script> script = Handle<Script>(Script::cast(script_val->value()));
 
   Handle<wasm::WasmDebugInfo> debug_info =
       wasm::GetDebugInfo(handle(script->wasm_object(), isolate));
   return *wasm::WasmDebugInfo::DisassembleFunction(
       debug_info, script->wasm_function_index());
 }
 
 }  // namespace internal
 }  // namespace v8