--- a/accessible/tests/browser/browser.ini
+++ b/accessible/tests/browser/browser.ini
@@ -8,17 +8,17 @@ support-files =
 [browser_shutdown_acc_reference.js]
 [browser_shutdown_doc_acc_reference.js]
 [browser_shutdown_multi_acc_reference_obj.js]
 [browser_shutdown_multi_acc_reference_doc.js]
 [browser_shutdown_multi_reference.js]
 [browser_shutdown_parent_own_reference.js]
 skip-if = !e10s || (os == 'win' && os_version == '5.1') # e10s specific test for a11y start/shutdown between parent and content.
 [browser_shutdown_proxy_acc_reference.js]
-skip-if = !e10s || (os == 'win') # e10s specific test for a11y start/shutdown between parent and content.
+skip-if = !e10s || (os == 'win') || stylo # e10s specific test for a11y start/shutdown between parent and content. bug 1390409 for stylo
 [browser_shutdown_proxy_doc_acc_reference.js]
 skip-if = !e10s || (os == 'win') # e10s specific test for a11y start/shutdown between parent and content.
 [browser_shutdown_multi_proxy_acc_reference_doc.js]
 skip-if = !e10s || (os == 'win') # e10s specific test for a11y start/shutdown between parent and content.
 [browser_shutdown_multi_proxy_acc_reference_obj.js]
 skip-if = !e10s || (os == 'win') # e10s specific test for a11y start/shutdown between parent and content.
 [browser_shutdown_remote_no_reference.js]
 skip-if = !e10s || (os == 'win' && os_version == '5.1') # e10s specific test for a11y start/shutdown between parent and content.

--- a/accessible/tests/browser/e10s/browser.ini
+++ b/accessible/tests/browser/e10s/browser.ini
@@ -21,17 +21,19 @@ support-files =
 skip-if = e10s && os == 'win' && debug # Bug 1338034, leaks
 [browser_caching_relations.js]
 [browser_caching_states.js]
 [browser_caching_value.js]
 
 # Events tests
 [browser_events_caretmove.js]
 [browser_events_hide.js]
+skip-if = stylo # bug 1390409
 [browser_events_show.js]
+skip-if = stylo # bug 1390409
 [browser_events_statechange.js]
 [browser_events_textchange.js]
 
 # Tree update tests
 [browser_treeupdate_ariadialog.js]
 [browser_treeupdate_ariaowns.js]
 [browser_treeupdate_canvas.js]
 [browser_treeupdate_cssoverflow.js]
@@ -43,10 +45,11 @@ skip-if = e10s && os == 'win' # Bug 1288
 [browser_treeupdate_list.js]
 [browser_treeupdate_list_editabledoc.js]
 [browser_treeupdate_listener.js]
 [browser_treeupdate_optgroup.js]
 [browser_treeupdate_removal.js]
 [browser_treeupdate_table.js]
 [browser_treeupdate_textleaf.js]
 [browser_treeupdate_visibility.js]
+skip-if = stylo # bug 1390409
 [browser_treeupdate_whitespace.js]
 skip-if = true # Failing due to incorrect index of test container children on document load.

--- a/browser/base/content/test/general/browser.ini
+++ b/browser/base/content/test/general/browser.ini
@@ -584,16 +584,17 @@ support-files =
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_blockHPKP.js]
 tags = psm
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_windowactivation.js]
 support-files =
   file_window_activation.html
   file_window_activation2.html
+skip-if = stylo # bug 1390694
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_contextmenu_childprocess.js]
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_bug963945.js]
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_domFullscreen_fullscreenMode.js]
 tags = fullscreen
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.

--- a/taskcluster/ci/test/test-sets.yml
+++ b/taskcluster/ci/test/test-sets.yml
@@ -83,16 +83,17 @@ stylo-tests:
     - cppunit
     - crashtest
     - reftest
     - reftest-stylo
     - web-platform-tests
     - web-platform-tests-reftests
     - mochitest
     - mochitest-a11y
+    - mochitest-browser-chrome
     - mochitest-browser-screenshots
     - mochitest-chrome
     - mochitest-clipboard
     - mochitest-gpu
     - mochitest-media
     - mochitest-webgl
 
 stylo-sequential-tests:

--- a/taskcluster/ci/test/tests.yml
+++ b/taskcluster/ci/test/tests.yml
@@ -547,16 +547,20 @@ mochitest-browser-chrome:
             linux32/debug: 5400
             default: 3600
     run-on-projects:
         by-test-platform:
             # Deactivate try on Buildbot, by default. We don't have enough machines
             windows8-64.*: ['mozilla-release', 'mozilla-beta', 'mozilla-central', 'mozilla-inbound', 'autoland']
             windows8-64-devedition/opt: built-projects  # No dev edition outside of supported branches
             windows10.*: []
+            linux64-stylo.*: ['autoland', 'mozilla-central', 'try']
+            linux64-stylo/debug: ['try']
+            macosx64-stylo/.*: ['mozilla-central', 'try']
+            windows7-32-stylo.*: ['autoland', 'mozilla-central', 'try']
             default: built-projects
     worker-type:
         by-test-platform:
             windows8-64.*: buildbot-bridge/buildbot-bridge
             default: null
     mozharness:
         mochitest-flavor: browser
         script: desktop_unittest.py
@@ -578,16 +582,21 @@ mochitest-browser-chrome:
                 default:
                     - --mochitest-suite=browser-chrome-chunked
     # Bug 1281241: migrating to m3.large instances
     instance-size:
         by-test-platform:
             linux64-jsdcov/opt: xlarge
             default: legacy
     allow-software-gl-layers: false
+    tier:
+        by-test-platform:
+            .*-stylo.*: 2
+            linux64-stylo/debug: 3
+            default: default
 
 mochitest-browser-screenshots:
     description: "Mochitest Browser Screenshots"
     suite: mochitest/browser-chrome-screenshots
     treeherder-symbol: tc-M(ss)
     loopback-video: true
     run-on-projects:
         by-test-platform:

--- a/toolkit/components/tooltiptext/tests/browser.ini
+++ b/toolkit/components/tooltiptext/tests/browser.ini
@@ -1,7 +1,8 @@
 [browser_bug329212.js]
 support-files = title_test.svg
+skip-if = stylo && os == 'win' # bug 1390726
 [browser_bug331772_xul_tooltiptext_in_html.js]
 support-files = xul_tooltiptext.xhtml
 [browser_bug561623.js]
 [browser_bug581947.js]
 [browser_input_file_tooltips.js]