[tracing] Implement composable memory usage estimators.

base/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # HOW TO WRITE CONDITIONALS IN THIS FILE
 # ======================================
 #
 # In many other places, one would write a conditional that expresses all the
 # cases when a source file is used or unused, and then either add or subtract
 # it from the sources list in that case
@@ skipping 918 matching lines @@
     "trace_event/memory_allocator_dump_guid.h",
     "trace_event/memory_dump_manager.cc",
     "trace_event/memory_dump_manager.h",
     "trace_event/memory_dump_provider.h",
     "trace_event/memory_dump_request_args.cc",
     "trace_event/memory_dump_request_args.h",
     "trace_event/memory_dump_session_state.cc",
     "trace_event/memory_dump_session_state.h",
     "trace_event/memory_infra_background_whitelist.cc",
     "trace_event/memory_infra_background_whitelist.h",
+    "trace_event/memory_usage_estimator.cc",
+    "trace_event/memory_usage_estimator.h",
     "trace_event/process_memory_dump.cc",
     "trace_event/process_memory_dump.h",
     "trace_event/process_memory_maps.cc",
     "trace_event/process_memory_maps.h",
     "trace_event/process_memory_totals.cc",
     "trace_event/process_memory_totals.h",
     "trace_event/trace_buffer.cc",
     "trace_event/trace_buffer.h",
     "trace_event/trace_category.h",
     "trace_event/trace_config.cc",
@@ skipping 1033 matching lines @@
     "tools_sanity_unittest.cc",
     "trace_event/blame_context_unittest.cc",
     "trace_event/heap_profiler_allocation_context_tracker_unittest.cc",
     "trace_event/heap_profiler_allocation_register_unittest.cc",
     "trace_event/heap_profiler_heap_dump_writer_unittest.cc",
     "trace_event/heap_profiler_stack_frame_deduplicator_unittest.cc",
     "trace_event/heap_profiler_type_name_deduplicator_unittest.cc",
     "trace_event/java_heap_dump_provider_android_unittest.cc",
     "trace_event/memory_allocator_dump_unittest.cc",
     "trace_event/memory_dump_manager_unittest.cc",
+    "trace_event/memory_usage_estimator_unittest.cc",
     "trace_event/process_memory_dump_unittest.cc",
     "trace_event/trace_category_unittest.cc",
     "trace_event/trace_config_unittest.cc",
     "trace_event/trace_event_argument_unittest.cc",
     "trace_event/trace_event_synthetic_delay_unittest.cc",
     "trace_event/trace_event_system_stats_monitor_unittest.cc",
     "trace_event/trace_event_unittest.cc",
     "tracked_objects_unittest.cc",
     "tuple_unittest.cc",
     "unguessable_token_unittest.cc",
@@ skipping 478 matching lines @@
 }
 
 fuzzer_test("base_json_correctness_fuzzer") {
   sources = [
     "json/correctness_fuzzer.cc",
   ]
   deps = [
     ":base",
   ]
 }