https://build.chromium.org/p/chromium.memory.full/builders/Windows%20Unit%20%28DrMemory%29/builds/130/steps/memory%20test%3A%20net/logs/stdio started reporting:

~~Dr.M~~ 
~~Dr.M~~ Error #1: INVALID HEAP ARGUMENT: allocated with Windows API layer, queried with C library layer
~~Dr.M~~ # 0 replace_malloc_usable_size                                                 [d:\drmemory_package\common\alloc_replace.c:2736]
~~Dr.M~~ # 1 ucrtbase.dll!mbtowc_l                                                     +0x328    (0x6c5435a9 <ucrtbase.dll+0x335a9>)
~~Dr.M~~ # 2 ucrtbase.dll!register_onexit_function                                     +0x41f    (0x6c5408c0 <ucrtbase.dll+0x308c0>)
~~Dr.M~~ # 3 ucrtbase.dll!register_onexit_function                                     +0x2cd    (0x6c54076e <ucrtbase.dll+0x3076e>)
~~Dr.M~~ # 4 ucrtbase.dll!register_onexit_function                                     +0x87     (0x6c540528 <ucrtbase.dll+0x30528>)
~~Dr.M~~ # 5 ucrtbase.dll!crt_atexit                                                   +0x11     (0x6c54d212 <ucrtbase.dll+0x3d212>)
~~Dr.M~~ # 6 _onexit                                                                    [f:\dd\vctools\crt\vcstartup\src\utility\utility.cpp:262]
~~Dr.M~~ # 7 atexit                                                                     [f:\dd\vctools\crt\vcstartup\src\utility\utility.cpp:276]
~~Dr.M~~ # 8 net::`anonymous namespace'::`dynamic initializer for 'kOtherword''         [net\ftp\ftp_auth_cache_unittest.cc:22]
~~Dr.M~~ # 9 __scrt_common_main_seh                                                     [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:221]
~~Dr.M~~ #10 KERNEL32.dll!BaseThreadInitThunk                                          +0x11     (0x748d337a <KERNEL32.dll+0x1337a>)
~~Dr.M~~ Note: @0:00:10.562 in thread 6032
~~Dr.M~~ Note: re-run with -malloc_callstacks (or -count_leaks) to add the allocation callstack.
~~Dr.M~~ 
~~Dr.M~~ Error #2: INVALID HEAP ARGUMENT: allocated with Windows API layer, queried with C library layer
~~Dr.M~~ # 0 replace_malloc_usable_size                                                 [d:\drmemory_package\common\alloc_replace.c:2736]
~~Dr.M~~ # 1 ucrtbase.dll!mbtowc_l                                                     +0x328    (0x6c5435a9 <ucrtbase.dll+0x335a9>)
~~Dr.M~~ # 2 ucrtbase.dll!register_onexit_function                                     +0x41f    (0x6c5408c0 <ucrtbase.dll+0x308c0>)
~~Dr.M~~ # 3 ucrtbase.dll!register_onexit_function                                     +0x2cd    (0x6c54076e <ucrtbase.dll+0x3076e>)
~~Dr.M~~ # 4 ucrtbase.dll!register_onexit_function                                     +0x87     (0x6c540528 <ucrtbase.dll+0x30528>)
~~Dr.M~~ # 5 ucrtbase.dll!crt_atexit                                                   +0x11     (0x6c54d212 <ucrtbase.dll+0x3d212>)
~~Dr.M~~ # 6 _onexit                                                                    [f:\dd\vctools\crt\vcstartup\src\utility\utility.cpp:262]
~~Dr.M~~ # 7 atexit                                                                     [f:\dd\vctools\crt\vcstartup\src\utility\utility.cpp:276]
~~Dr.M~~ # 8 net::`anonymous namespace'::`dynamic initializer for 'kFou''               [net\http\http_network_transaction_unittest.cc:118]
~~Dr.M~~ # 9 __scrt_common_main_seh                                                     [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:221]
~~Dr.M~~ #10 KERNEL32.dll!BaseThreadInitThunk                                          +0x11     (0x748d337a <KERNEL32.dll+0x1337a>)
~~Dr.M~~ Note: @0:00:10.749 in thread 6032
~~Dr.M~~ Note: re-run with -malloc_callstacks (or -count_leaks) to add the allocation callstack.

ftp_auth_cache_unittest.cc:22 is "const base::string16 kOtherword(ASCIIToUTF16("otherword"));"
http_network_transaction_unittest.cc:118 is "const base::string16 kFou(ASCIIToUTF16("fou"));"

I suspect another compiler/tool mismatch like issue 413215.