[heap profiler] Refactor intermediate storage classes in json_exporter

Remove Backtrace, BacktraceStorage.
Replace AllocationEvent with AllocationSite & AllocationMetrics.

BUG=923459

Change-Id: I7c1fa42e866c6cd6bb21a1f7d2c7ed4bd67d0919
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1574651
Commit-Queue: Alexei Filippov <[email protected]>
Reviewed-by: Erik Chen <[email protected]>
Cr-Commit-Position: refs/heads/master@{#652995}
diff --git a/components/services/heap_profiling/connection_manager.h b/components/services/heap_profiling/connection_manager.h
index 36ce1de..01d65b47 100644
--- a/components/services/heap_profiling/connection_manager.h
+++ b/components/services/heap_profiling/connection_manager.h
@@ -18,7 +18,7 @@
 #include "base/threading/thread.h"
 #include "base/timer/timer.h"
 #include "build/build_config.h"
-#include "components/services/heap_profiling/allocation_event.h"
+#include "components/services/heap_profiling/allocation.h"
 #include "components/services/heap_profiling/public/mojom/heap_profiling_service.mojom.h"
 #include "services/resource_coordinator/public/mojom/memory_instrumentation/memory_instrumentation.mojom.h"
 
@@ -78,9 +78,8 @@
       base::ProcessId pid,
       mojom::ProcessType process_type,
       bool strip_path_from_mapped_files,
-      uint32_t sampling_rate,
       bool success,
-      AllocationCountMap counts,
+      AllocationMap counts,
       ContextMap context,
       AddressToStringMap mapped_strings);