[tracing] Switch to new heap dump format.

base/trace_event/process_memory_dump.h

Index: base/trace_event/process_memory_dump.h
diff --git a/base/trace_event/process_memory_dump.h b/base/trace_event/process_memory_dump.h
index 6f8d167273327e2488ae30f12ca53928c810543d..d72a0877e0ccf8d70f82ff6ad7be219bab9e52b5 100644
--- a/base/trace_event/process_memory_dump.h
+++ b/base/trace_event/process_memory_dump.h
@@ -11,6 +11,7 @@
 #include <vector>
 
 #include "base/base_export.h"
+#include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_vector.h"
@@ -31,6 +32,7 @@
 namespace base {
 namespace trace_event {
 
+class AllocationRegister;
 class MemoryDumpSessionState;
 class TracedValue;
 
@@ -118,10 +120,7 @@ class BASE_EXPORT ProcessMemoryDump {
   const AllocatorDumpsMap& allocator_dumps() const { return allocator_dumps_; }
 
   // Dumps heap usage with |allocator_name|.
-  void DumpHeapUsage(const base::hash_map<base::trace_event::AllocationContext,
-                                          base::trace_event::AllocationMetrics>&
-                         metrics_by_context,
-                     base::trace_event::TraceEventMemoryOverhead& overhead,
+  void DumpHeapUsage(const AllocationRegister& allocation_register,
                      const char* allocator_name);
 
   // Adds an ownership relationship between two MemoryAllocatorDump(s) with the