memory-infra: Move dump level check to observer and rename session state

- Rename session_state to heap_profiler_serialization_state in MemoryDumpManager.
- Move IsDumpModeAllowed check from MemoryDumpManager to MemoryTracingObserver.

This further decouples MemoryDumpManager from tracing.

BUG=703184

Review-Url: https://codereview.chromium.org/2861133002
Cr-Original-Commit-Position: refs/heads/master@{#469721}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: b154afcbc07fcd0b31b1c59ef3c6c30c02bed13a
diff --git a/tools/gn/bootstrap/bootstrap.py b/tools/gn/bootstrap/bootstrap.py
index 399ccea..3901dd4 100755
--- a/tools/gn/bootstrap/bootstrap.py
+++ b/tools/gn/bootstrap/bootstrap.py
@@ -534,6 +534,7 @@
       'base/trace_event/heap_profiler_allocation_register.cc',
       'base/trace_event/heap_profiler_event_filter.cc',
       'base/trace_event/heap_profiler_heap_dump_writer.cc',
+      'base/trace_event/heap_profiler_serialization_state.cc',
       'base/trace_event/heap_profiler_stack_frame_deduplicator.cc',
       'base/trace_event/heap_profiler_type_name_deduplicator.cc',
       'base/trace_event/memory_allocator_dump.cc',
@@ -542,7 +543,6 @@
       'base/trace_event/memory_dump_provider_info.cc',
       'base/trace_event/memory_dump_request_args.cc',
       'base/trace_event/memory_dump_scheduler.cc',
-      'base/trace_event/memory_dump_session_state.cc',
       'base/trace_event/memory_infra_background_whitelist.cc',
       'base/trace_event/memory_peak_detector.cc',
       'base/trace_event/memory_tracing_observer.cc',