tools/gn: do not break bootstrap process on Windows

malloc_dump_provider.cc should be built only on Linux or Mac.

BUG=568437
TBR=brettw@chromium.org

Review URL: https://codereview.chromium.org/1521063002

Cr-Original-Commit-Position: refs/heads/master@{#364841}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 4514a7974f1acd2cd696aa3e1833c2e7be970668

tools/gn/bootstrap/bootstrap.py

diff --git a/tools/gn/bootstrap/bootstrap.py b/tools/gn/bootstrap/bootstrap.py
index 2dba1aa..5296ff3 100755
--- a/tools/gn/bootstrap/bootstrap.py
+++ b/tools/gn/bootstrap/bootstrap.py
@@ -249,7 +249,6 @@
       'base/trace_event/heap_profiler_allocation_context_tracker.cc',
       'base/trace_event/heap_profiler_stack_frame_deduplicator.cc',
       'base/trace_event/heap_profiler_type_name_deduplicator.cc',
-      'base/trace_event/malloc_dump_provider.cc',
       'base/trace_event/memory_allocator_dump.cc',
       'base/trace_event/memory_allocator_dump_guid.cc',
       'base/trace_event/memory_dump_manager.cc',
@@ -371,6 +370,7 @@
         'base/strings/sys_string_conversions_mac.mm',
         'base/time/time_mac.cc',
         'base/threading/platform_thread_mac.mm',
+        'base/trace_event/malloc_dump_provider.cc',
     ])
     static_libraries['libevent']['include_dirs'].extend([
         os.path.join(SRC_ROOT, 'third_party', 'libevent', 'mac')