Update documents after we introduced Mac.txt

We now have two files listing smoke tests. Default.txt for Fuchsia,
and Mac.txt for Mac10.12, 10.13 and 10.14.

Update the document accordingly.

Bug: 1317393
Change-Id: I5516941f8908a6fe4b2aad671f99db56e9cc79a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3618204
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Weizhong Xia <weizhong@google.com>
Cr-Commit-Position: refs/heads/main@{#998692}
diff --git a/docs/fuchsia/web_tests.md b/docs/fuchsia/web_tests.md
index 6c573b2..911f542 100644
--- a/docs/fuchsia/web_tests.md
+++ b/docs/fuchsia/web_tests.md
@@ -4,7 +4,7 @@
 [here](../testing/web_tests.md).
 
 Currently, only
-[a small subset of web tests](../../third_party/blink/web_tests/SmokeTests)
+[a small subset of web tests](../../third_party/blink/web_tests/SmokeTests/Default.txt)
 can be run on Fuchsia. Build the target `blink_tests` first before running any
 of the commands below:
 
@@ -25,4 +25,4 @@
 $ third_party/blink/tools/run_web_tests.py -t <output-dir> --platform=fuchsia
 --device=device --fuchsia-target-cpu=<device-cpu-arch>
 --fuchsia-out-dir=/path/to/fuchsia/outdir --fuchsia-host-ip=test.host.ip.address
-```
\ No newline at end of file
+```
diff --git a/docs/testing/web_test_expectations.md b/docs/testing/web_test_expectations.md
index 480cc44..38fc38d6 100644
--- a/docs/testing/web_test_expectations.md
+++ b/docs/testing/web_test_expectations.md
@@ -249,8 +249,6 @@
 * [SlowTests](../../third_party/blink/web_tests/SlowTests): Tests that take
   longer than the usual timeout to run. Slow tests are given 5x the usual
   timeout.
-* [SmokeTests](../../third_party/blink/web_tests/SmokeTests): A small subset
-  of tests that we run on the Fuchsia bots.
 * [StaleTestExpectations](../../third_party/blink/web_tests/StaleTestExpectations):
   Platform-specific lines that have been in TestExpectations for many months.
   They're moved here to get them out of the way of people doing rebaselines
diff --git a/docs/testing/web_tests.md b/docs/testing/web_tests.md
index 010e27f..b489ed9 100644
--- a/docs/testing/web_tests.md
+++ b/docs/testing/web_tests.md
@@ -83,13 +83,21 @@
 
 *** promo
 Currently only the tests listed in
-[SmokeTests](../../third_party/blink/web_tests/SmokeTests) are run on the
-Fuchsia bots, since running all web tests takes too long on Fuchshia. Most
-developers focus their Blink testing on Linux. We rely on the fact that the
+[Default.txt](../../third_party/blink/web_tests/SmokeTests/Default.txt) are run
+on the Fuchsia bots, since running all web tests takes too long on Fuchshia.
+Most developers focus their Blink testing on Linux. We rely on the fact that the
 Linux and Fuchsia behavior is nearly identical for scenarios outside those
 covered by the smoke tests.
 ***
 
+*** promo
+Similar to Fuchsia's case, the tests listed in [Mac.txt]
+(../../third_party/blink/web_tests/SmokeTests/Mac.txt)
+are run on older mac version bots. By doing this we reduced the resources needed to run
+the tests. This relies on the fact that the majority of web tests will behavior similarly on
+different mac versions.
+***
+
 To run only some of the tests, specify their directories or filenames as
 arguments to `run_web_tests.py` relative to the web test directory
 (`src/third_party/blink/web_tests`). For example, to run the fast form tests,