[tracing] Switch to new heap dump format.

base/trace_event/process_memory_dump.cc

Index: base/trace_event/process_memory_dump.cc
diff --git a/base/trace_event/process_memory_dump.cc b/base/trace_event/process_memory_dump.cc
index d8a51ef4fe1e193415b3933a6c1e947b62303998..7d720c4ed798eae9d70942577e1050a87b8315b9 100644
--- a/base/trace_event/process_memory_dump.cc
+++ b/base/trace_event/process_memory_dump.cc
@@ -11,8 +11,8 @@
 #include "base/memory/ptr_util.h"
 #include "base/process/process_metrics.h"
 #include "base/strings/stringprintf.h"
-#include "base/trace_event/heap_profiler_heap_dump_writer.h"
-#include "base/trace_event/heap_profiler_serialization_state.h"
+#include "base/trace_event/heap_profiler_allocation_register.h"
+#include "base/trace_event/heap_profiler_event_writer.h"
 #include "base/trace_event/memory_infra_background_whitelist.h"
 #include "base/trace_event/process_memory_totals.h"
 #include "base/trace_event/trace_event_argument.h"
@@ -247,12 +247,9 @@ MemoryAllocatorDump* ProcessMemoryDump::GetSharedGlobalAllocatorDump(
 }
 
 void ProcessMemoryDump::DumpHeapUsage(
-    const std::unordered_map<base::trace_event::AllocationContext,
-                             base::trace_event::AllocationMetrics>&
-        metrics_by_context,
-    base::trace_event::TraceEventMemoryOverhead& overhead,
+    const AllocationRegister& allocation_register,
     const char* allocator_name) {
-  if (!metrics_by_context.empty()) {
+  if (allocation_register.begin() != allocation_register.end()) {
     // We shouldn't end up here unless we're doing a detailed dump with
     // heap profiling enabled and if that is the case tracing should be
     // enabled which sets up the heap profiler serialization state.
@@ -261,11 +258,13 @@ void ProcessMemoryDump::DumpHeapUsage(
       return;
     }
     DCHECK_EQ(0ul, heap_dumps_.count(allocator_name));
-    std::unique_ptr<TracedValue> heap_dump = ExportHeapDump(
-        metrics_by_context, *heap_profiler_serialization_state());
+    std::unique_ptr<TracedValue> heap_dump = SerializeHeapDump(
+        allocation_register, *heap_profiler_serialization_state());
     heap_dumps_[allocator_name] = std::move(heap_dump);
   }
 
+  TraceEventMemoryOverhead overhead;
+  allocation_register.EstimateTraceMemoryOverhead(&overhead);
   std::string base_name = base::StringPrintf("tracing/heap_profiler_%s",
                                              allocator_name);
   overhead.DumpInto(base_name.c_str(), this);
@@ -330,10 +329,9 @@ void ProcessMemoryDump::AsValueInto(TracedValue* value) const {
   }
 
   if (heap_dumps_.size() > 0) {
-    value->BeginDictionary("heaps");
-    for (const auto& name_and_dump : heap_dumps_)
-      value->SetValueWithCopiedName(name_and_dump.first, *name_and_dump.second);
-    value->EndDictionary();  // "heaps"
+    auto profile_data = SerializeHeapProfileEventData(
+        heap_dumps_, *heap_profiler_serialization_state_);
+    value->SetValue("heaps_v2", *profile_data);
   }
 
   value->BeginArray("allocators_graph");