[docs/speed] Add links to list of perf lab platforms

Makes the list more discoverable and easy to find.

Also take the chance to rename chromium.perf -> chrome.perf waterfall.

Bug: 958739
Change-Id: Icb64f5290abb2bb31575956889faba23adf6c944
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1886853
Commit-Queue: Juan Antonio Navarro Pérez <perezju@chromium.org>
Commit-Queue: Sami Kyöstilä <skyostil@chromium.org>
Auto-Submit: Juan Antonio Navarro Pérez <perezju@chromium.org>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710296}

docs/speed/addressing_performance_regressions.md

@@ -7,11 +7,12 @@ and assigned a bug to you! What should you do? Read on...
 
 ## About our performance tests
 
-The [chromium.perf waterfall](perf_waterfall.md) is a continuous build which
-runs performance tests on dozens of devices across Windows, Mac, Linux, and
-Android Chrome and WebView. Often, a performance regression only affects a
-certain type of hardware or a certain operating system, which may be different
-than what you tested locally before landing your CL.
+The [chrome.perf waterfall](perf_waterfall.md) is a continuous build which
+runs performance tests on dozens of devices across Android, Windows,
+Mac, and Linux hardware; see [list of platforms](perf_lab_platforms.md).
+Often, a performance regression only affects a certain type of hardware or a
+certain operating system, which may be different than what you tested locally
+before landing your CL.
 
 Each test has an owner, named in
 [this spreadsheet](https://docs.google.com/spreadsheets/d/1xaAo0_SU3iDfGdqDJZX_jRV0QtkufwHUKH3kQKF3YQs/edit#gid=0),

docs/speed/perf_waterfall.md

@@ -2,9 +2,10 @@
 
 ## Overview
 
-The [chromium.perf waterfall](https://ci.chromium.org/p/chrome/g/chrome.perf/console)
+The [chrome.perf waterfall](https://ci.chromium.org/p/chrome/g/chrome.perf/console)
 continuously builds and runs our performance tests on real Android, Windows,
-Mac, and Linux hardware. Results are reported to the
+Mac, and Linux hardware; see [list of platforms](perf_lab_platforms.md).
+Results are reported to the
 [Performance Dashboard](https://chromeperf.appspot.com/) for analysis. The
 [Perfbot Health Sheriffing Rotation](bot_health_sheriffing/main.md) ensures that the benchmarks stay green. The [Perf Sheriff Rotation](perf_regression_sheriffing.md) ensures that any regressions detected by those benchmarks are addressed quickly. Together, these rotations maintain
 [Chrome's Core Principles](https://www.chromium.org/developers/core-principles)