--- a/layout/style/test/moz.build
+++ b/layout/style/test/moz.build
@@ -118,27 +118,16 @@ TEST_HARNESS_FILES.testing.mochitest.tes
     '/layout/reftests/fonts/Ahem.ttf',
     '/layout/reftests/svg/as-image/lime100x100.svg',
     '/layout/reftests/svg/as-image/svg-image-visited-1-helper.svg',
     '/layout/reftests/svg/as-image/svg-image-visited-2-helper.svg',
     '/layout/reftests/svg/pseudo-classes-02-ref.svg',
     '/layout/reftests/svg/pseudo-classes-02.svg',
 ]
 
-if CONFIG['MOZ_STYLO']:
-    TEST_HARNESS_FILES.testing.mochitest.tests.layout.style.test += [
-        'stylo-failures.md',
-    ]
-    TEST_HARNESS_FILES.testing.mochitest.chrome.layout.style.test += [
-        'stylo-failures.md',
-    ]
-    # TEST_HARNESS_FILES.testing.mochitest.browser.layout.style.test += [
-    #     'stylo-failures.md',
-    # ]
-
 DEFINES['MOZILLA_INTERNAL_API'] = True
 if CONFIG['MOZ_ENABLE_MASK_AS_SHORTHAND']:
    HOST_DEFINES['MOZ_ENABLE_MASK_AS_SHORTHAND'] = True
 
 if CONFIG['COMPILE_ENVIRONMENT']:
     GENERATED_FILES += ['css_properties.js']
     GENERATED_FILES['css_properties.js'].script = 'gen-css-properties.py'
     GENERATED_FILES['css_properties.js'].inputs = [

deleted file mode 100644
--- a/layout/style/test/stylo-failures.md
+++ /dev/null
@@ -1,51 +0,0 @@
-This file describes test failures we currently have for stylo.
-
-Failure patterns are described in the following format:
-* test_name.html [number]
-* test_name.html `pattern` [number]
-* test_name.html: description [number]
-* test_name.html `pattern`: description [number]
-* test_name.html asserts [number]
-* test_name.html asserts: description [number]
-
-In which
-* test_name.html is the name of the test. It could be "..." which means
-  the same name as the previous failure pattern.
-* description is a comment for the supposed reason of the failure.
-* [number] is the expected count of the failure, which can be a "*" meaning
-  any positive number.
-* `pattern` is a substring of the failure message. If there are multiple items
-  for the same test file, a failure is captured by the first matched pattern.
-  For example, if there is a failure with message "foo bar", and there is a
-  pattern `foo` followed by a pattern `bar`, this failure would be counted in
-  the pattern `foo`.
-* "asserts" means it is for assertion. Number of assertions of a same test is
-  accumulated, unlike `pattern`. And number of assertions cannot be "*".
-
-Any line which doesn't follow the format above would be ignored like comment.
-
-To use this file, you need to add `--failure-pattern-file=stylo-failures.md`
-to mochitest command.
-
-## Failures
-
-* Media query support:
-  * test_media_queries_dynamic_xbl.html: xbl support bug 1382078 [1]
-* Animation support:
-  * SMIL Animation
-    * test_restyles_in_smil_animation.html [2]
-* Incorrect serialization
-  * place-{content,items,self} shorthands bug 1363971
-    * test_align_shorthand_serialization.html [6]
-* Unit should be preserved after parsing servo/servo#15346
-* test_author_specified_style.html: support serializing color as author specified bug 1348165 [27]
-* browser_newtab_share_rule_processors.js: agent style sheet sharing [1]
-* test_selectors_on_anonymous_content.html: xbl and :nth-child bug 1382102 [1]
-
-## Assertions
-
-## Need Gecko change
-
-## Unknown / Unsure
-
-## Ignore

--- a/taskcluster/ci/test/test-sets.yml
+++ b/taskcluster/ci/test/test-sets.yml
@@ -79,25 +79,30 @@ awsy-stylo-sequential:
 ##
 # Limited test sets for specific platforms
 
 stylo-tests:
     - cppunit
     - crashtest
     - reftest
     - reftest-stylo
-    - mochitest-style
-    - mochitest-chrome-style
     - web-platform-tests
     - web-platform-tests-reftests
+    - mochitest
+    - mochitest-browser-screenshots
+    - mochitest-chrome
+    - mochitest-clipboard
+    - mochitest-gpu
+    - mochitest-media
+    - mochitest-webgl
 
 stylo-sequential-tests:
     - crashtest
     - reftest-stylo
-    - mochitest-style
+    - mochitest
 
 qr-tests:
     - cppunit
     - crashtest
     - gtest
     - jittest
     - jsreftest
     - mochitest-a11y

--- a/taskcluster/ci/test/tests.yml
+++ b/taskcluster/ci/test/tests.yml
@@ -444,21 +444,28 @@ mochitest:
             default: 5400
     allow-software-gl-layers: false
     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']
+            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
+    tier:
+        by-test-platform:
+            macosx64-stylo/.*: 2
+            default: default
     mozharness:
         by-test-platform:
             android.*:
                 mochitest-flavor: plain
                 script: android_emulator_unittest.py
                 no-read-buildbot-config: true
                 config:
                     - android/androidarm_4_3.py
@@ -623,16 +630,19 @@ mochitest-chrome:
             android-4.3-arm7-api-15/debug: 4
             android.*: 2
             default: 3
     max-run-time: 3600
     e10s: false
     run-on-projects:
         by-test-platform:
             windows7-32.*: ['try']
+            linux64-stylo/debug: ['try']
+            linux64-stylo.*: ['autoland', 'mozilla-central', 'try']
+            macosx64-stylo/.*: ['mozilla-central', 'try']
             default: built-projects
     worker-type:
         by-test-platform:
             windows7-32.*: buildbot-bridge/buildbot-bridge
             windows8-64.*: buildbot-bridge/buildbot-bridge
             default: null
     mozharness:
         by-test-platform:
@@ -663,54 +673,33 @@ mochitest-chrome:
                         linux.*:
                             - unittests/linux_unittest.py
                             - remove_executables.py
                 extra-options:
                     - --mochitest-suite=chrome
     tier:
         by-test-platform:
             windows7-32.*: 2
+            macosx64-stylo/.*: 2
+            linux64-stylo/debug: 3
             default: default
 
-mochitest-chrome-style:
-    description: "Mochitest chrome run for style system"
-    suite: mochitest/chrome-style
-    treeherder-symbol: tc-M(cs)
-    loopback-video: true
-    run-on-projects:
-        by-test-platform:
-            .*-stylo.*: ['autoland', 'mozilla-central', 'try']
-            default: built-projects
-    e10s: false
-    mozharness:
-        mochitest-flavor: chrome
-        script: desktop_unittest.py
-        no-read-buildbot-config: true
-        config:
-            by-test-platform:
-                windows.*:
-                    - unittests/win_taskcluster_unittest.py
-                macosx.*:
-                    - unittests/mac_unittest.py
-                default:
-                    - unittests/linux_unittest.py
-                    - remove_executables.py
-        extra-options:
-            - --mochitest-suite=chrome-style
-
 mochitest-clipboard:
     description: "Mochitest clipboard run"
     suite: mochitest/clipboard
     treeherder-symbol: tc-M(cl)
     loopback-video: true
     virtualization: hardware
     instance-size: xlarge
     run-on-projects:
         by-test-platform:
             windows.*: ['try']
+            linux64-stylo/debug: ['try']
+            linux64-stylo.*: ['autoland', 'mozilla-central', 'try']
+            macosx64-stylo/.*: ['mozilla-central', 'try']
             default: built-projects
     worker-type:
         by-test-platform:
             windows7-32.*: buildbot-bridge/buildbot-bridge
             windows8-64.*: buildbot-bridge/buildbot-bridge
             default: null
     mozharness:
         by-test-platform:
@@ -738,16 +727,18 @@ mochitest-clipboard:
                         linux.*:
                             - unittests/linux_unittest.py
                             - remove_executables.py
                 extra-options:
                     - --mochitest-suite=plain-clipboard,chrome-clipboard,browser-chrome-clipboard
     tier:
         by-test-platform:
             windows7-32.*: 2
+            macosx64-stylo/.*: 2
+            linux64-stylo/debug: 3
             default: default
 
 mochitest-devtools-chrome:
     description: "Mochitest devtools-chrome run"
     suite:
         by-test-platform:
             linux64-jsdcov/opt: mochitest/mochitest-devtools-chrome-coverage
             default: mochitest/mochitest-devtools-chrome-chunked
@@ -760,17 +751,19 @@ mochitest-devtools-chrome:
             macosx.*: 8
             default: 10
     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.*: []
-            .*-stylo.*: ['autoland', 'mozilla-central', 'try']
+            linux64-stylo.*: ['autoland', 'mozilla-central', '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
     e10s:
         by-test-platform:
             linux64-jsdcov/opt: false
@@ -810,16 +803,19 @@ mochitest-gpu:
     loopback-video: true
     virtualization: virtual-with-gpu
     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']
+            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:
         by-test-platform:
             android.*:
@@ -845,16 +841,17 @@ mochitest-gpu:
                         linux.*:
                             - unittests/linux_unittest.py
                             - remove_executables.py
                 extra-options:
                     - --mochitest-suite=plain-gpu,chrome-gpu,browser-chrome-gpu
     tier:
         by-test-platform:
             linux64-qr/.*: 1
+            macosx64-stylo/.*: 2
             default: default
 
 mochitest-jetpack:
     description: "Mochitest jetpack run"
     suite: mochitest/jetpack-package
     treeherder-symbol: tc-M(JP)
     loopback-video: true
     e10s: false
@@ -894,16 +891,19 @@ mochitest-media:
             windows8-64.*: 1
             default: 3
     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']
+            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:
         by-test-platform:
             android.*:
@@ -932,43 +932,19 @@ mochitest-media:
                         linux.*:
                             - unittests/linux_unittest.py
                             - remove_executables.py
                 extra-options:
                     - --mochitest-suite=mochitest-media
     tier:
         by-test-platform:
             linux64-qr/.*: 1
+            macosx64-stylo/.*: 2
             default: default
 
-mochitest-style:
-    description: "Mochitest plain run for style system"
-    suite: mochitest/plain-style
-    treeherder-symbol: tc-M(s)
-    loopback-video: true
-    run-on-projects:
-        by-test-platform:
-            .*-stylo.*: ['autoland', 'mozilla-central', 'try']
-            default: built-projects
-    mozharness:
-        mochitest-flavor: plain
-        script: desktop_unittest.py
-        no-read-buildbot-config: true
-        config:
-            by-test-platform:
-                windows.*:
-                    - unittests/win_taskcluster_unittest.py
-                macosx.*:
-                    - unittests/mac_unittest.py
-                default:
-                    - unittests/linux_unittest.py
-                    - remove_executables.py
-        extra-options:
-            - --mochitest-suite=plain-style
-
 mochitest-valgrind:
     description: "Mochitest plain Valgrind run"
     suite: mochitest/valgrind-plain
     treeherder-symbol: tc-M-V()
     run-on-projects: []
     loopback-video: true
     chunks: 40
     max-run-time: 14400
@@ -999,16 +975,19 @@ mochitest-webgl:
     treeherder-symbol: tc-M(gl)
     virtualization: virtual-with-gpu
     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']
+            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
     chunks:
         by-test-platform:
             android.*: 10
@@ -1049,16 +1028,17 @@ mochitest-webgl:
                         linux.*:
                             - unittests/linux_unittest.py
                             - remove_executables.py
                 extra-options:
                     - --mochitest-suite=mochitest-gl
     tier:
         by-test-platform:
             linux64-qr/.*: 1
+            macosx64-stylo/.*: 2
             default: default
 
 reftest:
     description: "Reftest run"
     suite: reftest/reftest
     treeherder-symbol: tc-R(R)
     run-on-projects:
         by-test-platform:

--- a/testing/mozharness/configs/unittests/linux_unittest.py
+++ b/testing/mozharness/configs/unittests/linux_unittest.py
@@ -202,18 +202,16 @@ config = {
         "mochitest-gl": ["--subsuite=webgl"],
         "mochitest-devtools-chrome": ["--flavor=browser", "--subsuite=devtools"],
         "mochitest-devtools-chrome-chunked": ["--flavor=browser", "--subsuite=devtools", "--chunk-by-runtime"],
         "mochitest-devtools-chrome-coverage": ["--flavor=browser", "--subsuite=devtools", "--chunk-by-runtime", "--timeout=1200"],
         "jetpack-package": ["--flavor=jetpack-package"],
         "jetpack-package-clipboard": ["--flavor=jetpack-package", "--subsuite=clipboard"],
         "jetpack-addon": ["--flavor=jetpack-addon"],
         "a11y": ["--flavor=a11y"],
-        "plain-style": ["--failure-pattern-file=stylo-failures.md", "layout/style/test", "dom/smil/test", "dom/animation/test"],
-        "chrome-style": ["--flavor=chrome", "--failure-pattern-file=../stylo-failures.md", "layout/style/test/chrome", "dom/animation/test"],
     },
     # local reftest suites
     "all_reftest_suites": {
         "crashtest": {
             "options": ["--suite=crashtest"],
             "tests": ["tests/reftest/tests/testing/crashtest/crashtests.list"]
         },
         "jsreftest": {

--- a/testing/mozharness/configs/unittests/mac_unittest.py
+++ b/testing/mozharness/configs/unittests/mac_unittest.py
@@ -165,18 +165,16 @@ config = {
         "browser-chrome-screenshots": ["--flavor=browser", "--subsuite=screenshots"],
         "mochitest-gl": ["--subsuite=webgl"],
         "mochitest-devtools-chrome": ["--flavor=browser", "--subsuite=devtools"],
         "mochitest-devtools-chrome-chunked": ["--flavor=browser", "--subsuite=devtools", "--chunk-by-runtime"],
         "jetpack-package": ["--flavor=jetpack-package"],
         "jetpack-package-clipboard": ["--flavor=jetpack-package", "--subsuite=clipboard"],
         "jetpack-addon": ["--flavor=jetpack-addon"],
         "a11y": ["--flavor=a11y"],
-        "plain-style": ["--failure-pattern-file=stylo-failures.md", "layout/style/test", "dom/smil/test", "dom/animation/test"],
-        "chrome-style": ["--flavor=chrome", "--failure-pattern-file=../stylo-failures.md", "layout/style/test/chrome", "dom/animation/test"],
     },
     # local reftest suites
     "all_reftest_suites": {
         "crashtest": {
             'options': ["--suite=crashtest"],
             'tests': ["tests/reftest/tests/testing/crashtest/crashtests.list"]
         },
         "jsreftest": {

--- a/testing/mozharness/configs/unittests/win_taskcluster_unittest.py
+++ b/testing/mozharness/configs/unittests/win_taskcluster_unittest.py
@@ -177,18 +177,16 @@ config = {
         "mochitest-gl": ["--subsuite=webgl"],
         "mochitest-devtools-chrome": ["--flavor=browser", "--subsuite=devtools"],
         "mochitest-devtools-chrome-chunked": ["--flavor=browser", "--subsuite=devtools", "--chunk-by-runtime"],
         "mochitest-metro-chrome": ["--flavor=browser", "--metro-immersive"],
         "jetpack-package": ["--flavor=jetpack-package"],
         "jetpack-package-clipboard": ["--flavor=jetpack-package", "--subsuite=clipboard"],
         "jetpack-addon": ["--flavor=jetpack-addon"],
         "a11y": ["--flavor=a11y"],
-        "plain-style": ["--failure-pattern-file=stylo-failures.md", "layout/style/test", "dom/smil/test", "dom/animation/test"],
-        "chrome-style": ["--flavor=chrome", "--failure-pattern-file=../stylo-failures.md", "layout/style/test/chrome", "dom/animation/test"],
     },
     # local reftest suites
     "all_reftest_suites": {
         "crashtest": {
             'options': ["--suite=crashtest"],
             'tests': ["tests/reftest/tests/testing/crashtest/crashtests.list"]
         },
         "jsreftest": {