I care about deterministic build files because I often mount my build directory at different locations (eg. in a shared directory inside a VM).

Right now, the generated build files on Linux with default configuration has just a few lines that depend on the name of the path to the source directory, or the name of the build directory relative to the source directory.  The diff is shown below.  We should fix this and perhaps add a step on a CQ bot that simply does "gn gen out/Default1; gn gen out/Default2; diff -ru out/Default1 out/Default2" and "grep `pwd` out/Defualt1 -r".

thomasanderson@thomasanderson:~$ diff -ru dev/chromium_official/src/out/Default1/ dev/chromium_1/src/out/Default2
diff -ru dev/chromium_official/src/out/Default1/toolchain.ninja dev/chromium_1/src/out/Default2/toolchain.ninja
--- dev/chromium_official/src/out/Default1/toolchain.ninja	2018-08-06 16:07:08.617735701 -0700
+++ dev/chromium_1/src/out/Default2/toolchain.ninja	2018-08-06 16:22:19.960980339 -0700
@@ -15079,7 +15079,7 @@
 subninja obj/components/url_formatter/unit_tests.ninja
 subninja obj/components/url_formatter/url_formatter.ninja
 rule __components_url_formatter_top_domains_generate_top_domains_test_trie___build_toolchain_linux_clang_x64__rule
-  command = python ../../build/gn_run_binary.py top_domain_generator /usr/local/google/home/thomasanderson/dev/chromium_official/src/components/url_formatter/top_domains/test_domains.skeletons /usr/local/google/home/thomasanderson/dev/chromium_official/src/components/url_formatter/top_domains/top_domains_trie.template gen/components/url_formatter/top_domains/test_domains-trie-inc.cc
+  command = python ../../build/gn_run_binary.py top_domain_generator /usr/local/google/home/thomasanderson/dev/chromium_1/src/components/url_formatter/top_domains/test_domains.skeletons /usr/local/google/home/thomasanderson/dev/chromium_1/src/components/url_formatter/top_domains/top_domains_trie.template gen/components/url_formatter/top_domains/test_domains-trie-inc.cc
   description = ACTION //components/url_formatter/top_domains:generate_top_domains_test_trie(//build/toolchain/linux:clang_x64)
   restat = 1
   pool = build_toolchain_action_pool
@@ -15088,7 +15088,7 @@
 
 build obj/components/url_formatter/top_domains/generate_top_domains_test_trie.stamp: stamp gen/components/url_formatter/top_domains/test_domains-trie-inc.cc
 rule __components_url_formatter_top_domains_generate_top_domains_trie___build_toolchain_linux_clang_x64__rule
-  command = python ../../build/gn_run_binary.py top_domain_generator /usr/local/google/home/thomasanderson/dev/chromium_official/src/components/url_formatter/top_domains/alexa_domains.skeletons /usr/local/google/home/thomasanderson/dev/chromium_official/src/components/url_formatter/top_domains/top_domains_trie.template gen/components/url_formatter/top_domains/alexa_domains-trie-inc.cc
+  command = python ../../build/gn_run_binary.py top_domain_generator /usr/local/google/home/thomasanderson/dev/chromium_1/src/components/url_formatter/top_domains/alexa_domains.skeletons /usr/local/google/home/thomasanderson/dev/chromium_1/src/components/url_formatter/top_domains/top_domains_trie.template gen/components/url_formatter/top_domains/alexa_domains-trie-inc.cc
   description = ACTION //components/url_formatter/top_domains:generate_top_domains_trie(//build/toolchain/linux:clang_x64)
   restat = 1
   pool = build_toolchain_action_pool
@@ -32207,7 +32207,7 @@
 subninja obj/testing/libfuzzer/fuzzers/javascript_parser_proto.ninja
 subninja obj/testing/libfuzzer/fuzzers/javascript_parser_proto_fuzzer.ninja
 rule __testing_libfuzzer_fuzzers_javascript_parser_proto_fuzzer.owners___build_toolchain_linux_clang_x64__rule
-  command = python ../../testing/libfuzzer/gen_fuzzer_owners.py --owners javascript_parser_proto_fuzzer.owners --sources out/Default1/gen/testing/libfuzzer/fuzzers/javascript_parser_proto_to_string.cc testing/libfuzzer/fuzzers/javascript_parser_proto_fuzzer.cc testing/libfuzzer/fuzzers/javascript_parser_proto_to_string.h
+  command = python ../../testing/libfuzzer/gen_fuzzer_owners.py --owners javascript_parser_proto_fuzzer.owners --sources out/Default2/gen/testing/libfuzzer/fuzzers/javascript_parser_proto_to_string.cc testing/libfuzzer/fuzzers/javascript_parser_proto_fuzzer.cc testing/libfuzzer/fuzzers/javascript_parser_proto_to_string.h
   description = ACTION //testing/libfuzzer/fuzzers:javascript_parser_proto_fuzzer.owners(//build/toolchain/linux:clang_x64)
   restat = 1
   pool = build_toolchain_action_pool