Move V8 GC trace events to their own catergory.

src/heap/gc-tracer.h

 // 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.
 
 #ifndef V8_HEAP_GC_TRACER_H_
 #define V8_HEAP_GC_TRACER_H_
 
 #include "src/base/compiler-specific.h"
 #include "src/base/platform/platform.h"
 #include "src/counters.h"
@@ skipping 94 matching lines @@
   F(SCAVENGER_OBJECT_GROUPS)                       \
   F(SCAVENGER_OLD_TO_NEW_POINTERS)                 \
   F(SCAVENGER_ROOTS)                               \
   F(SCAVENGER_SCAVENGE)                            \
   F(SCAVENGER_SEMISPACE)                           \
   F(SCAVENGER_WEAK)
 
 #define TRACE_GC(tracer, scope_id)                             \
   GCTracer::Scope::ScopeId gc_tracer_scope_id(scope_id);       \
   GCTracer::Scope gc_tracer_scope(tracer, gc_tracer_scope_id); \
-  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8"),                \
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.gc"),             \
                GCTracer::Scope::Name(gc_tracer_scope_id))
 
 // GCTracer collects and prints ONE line after each garbage collector
 // invocation IFF --trace_gc is used.
 // TODO(ernstm): Unit tests.
 class GCTracer {
  public:
   class Scope {
    public:
     enum ScopeId {
@@ skipping 364 matching lines @@
   RingBuffer<BytesAndDuration> recorded_old_generation_allocations_;
   RingBuffer<double> recorded_context_disposal_times_;
   RingBuffer<double> recorded_survival_ratios_;
 
   DISALLOW_COPY_AND_ASSIGN(GCTracer);
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_GC_TRACER_H_