[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 881 matching lines @@
     "timer/hi_res_timer_manager_win.cc",
     "timer/mock_timer.cc",
     "timer/mock_timer.h",
     "timer/timer.cc",
     "timer/timer.h",
     "trace_event/auto_open_close_event.cc",
     "trace_event/auto_open_close_event.h",
     "trace_event/blame_context.cc",
     "trace_event/blame_context.h",
     "trace_event/common/trace_event_common.h",
+    "trace_event/estimate_memory_usage.h",
     "trace_event/heap_profiler.h",
     "trace_event/heap_profiler_allocation_context.cc",
     "trace_event/heap_profiler_allocation_context.h",
     "trace_event/heap_profiler_allocation_context_tracker.cc",
     "trace_event/heap_profiler_allocation_context_tracker.h",
     "trace_event/heap_profiler_allocation_register.cc",
     "trace_event/heap_profiler_allocation_register.h",
     "trace_event/heap_profiler_allocation_register_posix.cc",
     "trace_event/heap_profiler_allocation_register_win.cc",
     "trace_event/heap_profiler_heap_dump_writer.cc",
@@ skipping 1222 matching lines @@
 
   if (is_win) {
     deps += [ "//base:scoped_handle_test_dll" ]
     if (current_cpu == "x64") {
       sources += [ "profiler/win32_stack_frame_unwinder_unittest.cc" ]
       deps += [ ":base_profiler_test_support_library" ]
     }
   }
 
   if (use_experimental_allocator_shim) {
-    sources += [ "allocator/allocator_shim_unittest.cc" ]
+    sources += [
+      "allocator/allocator_shim_unittest.cc",
+      "trace_event/estimate_memory_usage_unittest.cc",
+    ]
   }
 
   # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 
   # Symbols for crashes when running tests on swarming.
   if (symbol_level > 0) {
     if (is_win) {
       data += [ "$root_out_dir/base_unittests.exe.pdb" ]
     } else if (is_mac) {
@@ skipping 312 matching lines @@
 }
 
 fuzzer_test("base_json_correctness_fuzzer") {
   sources = [
     "json/correctness_fuzzer.cc",
   ]
   deps = [
     ":base",
   ]
 }