--- a/devtools/client/animationinspector/test/browser.ini
+++ b/devtools/client/animationinspector/test/browser.ini
@@ -43,18 +43,19 @@ skip-if = os == "linux" && !debug # Bug 
 [browser_animation_shows_player_on_valid_node.js]
 [browser_animation_spacebar_toggles_animations.js]
 [browser_animation_spacebar_toggles_node_animations.js]
 [browser_animation_target_highlight_select.js]
 [browser_animation_target_highlighter_lock.js]
 [browser_animation_timeline_currentTime.js]
 [browser_animation_timeline_header.js]
 [browser_animation_timeline_iterationStart.js]
-[browser_animation_timeline_pause_button.js]
-skip-if = os == "linux" && bits == 32 # Bug 1220974
+[browser_animation_timeline_pause_button_01.js]
+[browser_animation_timeline_pause_button_02.js]
+[browser_animation_timeline_pause_button_03.js]
 [browser_animation_timeline_rate_selector.js]
 [browser_animation_timeline_rewind_button.js]
 [browser_animation_timeline_scrubber_exists.js]
 [browser_animation_timeline_scrubber_movable.js]
 [browser_animation_timeline_scrubber_moves.js]
 [browser_animation_timeline_shows_delay.js]
 [browser_animation_timeline_shows_endDelay.js]
 [browser_animation_timeline_shows_iterations.js]

rename from devtools/client/animationinspector/test/browser_animation_timeline_pause_button.js
rename to devtools/client/animationinspector/test/browser_animation_timeline_pause_button_01.js
--- a/devtools/client/animationinspector/test/browser_animation_timeline_pause_button.js
+++ b/devtools/client/animationinspector/test/browser_animation_timeline_pause_button_01.js
@@ -1,110 +1,34 @@
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
  http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 requestLongerTimeout(2);
 
-// Check that the timeline toolbar contains a pause button and that this pause
-// button can be clicked. Check that when it is, the current animations
-// displayed in the timeline get their playstates changed accordingly, and check
-// that the scrubber resumes/stops moving.
-// Also checks that the button goes to the right state when the scrubber has
-// reached the end of the timeline: continues to be in playing mode for infinite
-// animations, goes to paused mode otherwise.
-// And test that clicking the button once the scrubber has reached the end of
-// the timeline does the right thing.
+// Check that the timeline toolbar contains a pause button and that this pause button can
+// be clicked. Check that when it is, the button changes state and the scrubber stops and
+// resumes.
 
 add_task(function* () {
   yield addTab(URL_ROOT + "doc_simple_animation.html");
 
-  let {panel, inspector} = yield openAnimationInspector();
-  let timeline = panel.animationsTimelineComponent;
+  let {panel} = yield openAnimationInspector();
   let btn = panel.playTimelineButtonEl;
 
   ok(btn, "The play/pause button exists");
-  ok(!btn.classList.contains("paused"),
-     "The play/pause button is in its playing state");
+  ok(!btn.classList.contains("paused"), "The play/pause button is in its playing state");
 
   info("Click on the button to pause all timeline animations");
   yield clickTimelinePlayPauseButton(panel);
 
-  ok(btn.classList.contains("paused"),
-     "The play/pause button is in its paused state");
+  ok(btn.classList.contains("paused"), "The play/pause button is in its paused state");
   yield assertScrubberMoving(panel, false);
 
   info("Click again on the button to play all timeline animations");
   yield clickTimelinePlayPauseButton(panel);
 
   ok(!btn.classList.contains("paused"),
      "The play/pause button is in its playing state again");
   yield assertScrubberMoving(panel, true);
-
-  // Some animations on the test page are infinite, so the scrubber won't stop
-  // at the end of the timeline, and the button should remain in play mode.
-  info("Select an infinite animation, reload the page and wait for the " +
-       "animation to complete");
-  yield selectNodeAndWaitForAnimations(".multi", inspector);
-  yield reloadTab(inspector);
-  yield waitForOutOfBoundScrubber(timeline);
-
-  ok(!btn.classList.contains("paused"),
-     "The button is in its playing state still, animations are infinite.");
-  yield assertScrubberMoving(panel, true);
-
-  info("Click on the button after the scrubber has moved out of bounds");
-  yield clickTimelinePlayPauseButton(panel);
-
-  ok(btn.classList.contains("paused"),
-     "The button can be paused after the scrubber has moved out of bounds");
-  yield assertScrubberMoving(panel, false);
-
-  // For a finite animation though, once the scrubber reaches the end of the
-  // timeline, it should go back to paused mode.
-  info("Select a finite animation, reload the page and wait for the " +
-       "animation to complete");
-  yield selectNodeAndWaitForAnimations(".negative-delay", inspector);
-
-  let onScrubberStopped = waitForScrubberStopped(timeline);
-  yield reloadTab(inspector);
-  yield onScrubberStopped;
-
-  ok(btn.classList.contains("paused"),
-     "The button is in paused state once finite animations are done");
-  yield assertScrubberMoving(panel, false);
-
-  info("Click again on the button to play the animation from the start again");
-  yield clickTimelinePlayPauseButton(panel);
-
-  ok(!btn.classList.contains("paused"),
-     "Clicking the button once finite animations are done should restart them");
-  yield assertScrubberMoving(panel, true);
 });
-
-function waitForOutOfBoundScrubber({win, scrubberEl}) {
-  return new Promise(resolve => {
-    function check() {
-      let pos = scrubberEl.getBoxQuads()[0].bounds.right;
-      let width = win.document.documentElement.offsetWidth;
-      if (pos >= width) {
-        setTimeout(resolve, 50);
-      } else {
-        setTimeout(check, 50);
-      }
-    }
-    check();
-  });
-}
-
-function waitForScrubberStopped(timeline) {
-  return new Promise(resolve => {
-    timeline.on("timeline-data-changed",
-      function onTimelineData(e, {isMoving}) {
-        if (!isMoving) {
-          timeline.off("timeline-data-changed", onTimelineData);
-          resolve();
-        }
-      });
-  });
-}

new file mode 100644
--- /dev/null
+++ b/devtools/client/animationinspector/test/browser_animation_timeline_pause_button_02.js
@@ -0,0 +1,48 @@
+/* vim: set ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+requestLongerTimeout(2);
+
+// Checks that the play/pause button goes to the right state when the scrubber has reached
+// the end of the timeline but there are infinite animations playing.
+
+add_task(function* () {
+  yield addTab(URL_ROOT + "doc_simple_animation.html");
+
+  let {panel, inspector} = yield openAnimationInspector();
+  let timeline = panel.animationsTimelineComponent;
+  let btn = panel.playTimelineButtonEl;
+
+  info("Select an infinite animation and wait for the scrubber to reach the end");
+  yield selectNodeAndWaitForAnimations(".multi", inspector);
+  yield waitForOutOfBoundScrubber(timeline);
+
+  ok(!btn.classList.contains("paused"),
+     "The button is in its playing state still, animations are infinite.");
+  yield assertScrubberMoving(panel, true);
+
+  info("Click on the button after the scrubber has moved out of bounds");
+  yield clickTimelinePlayPauseButton(panel);
+
+  ok(btn.classList.contains("paused"),
+     "The button can be paused after the scrubber has moved out of bounds");
+  yield assertScrubberMoving(panel, false);
+});
+
+function waitForOutOfBoundScrubber({win, scrubberEl}) {
+  return new Promise(resolve => {
+    function check() {
+      let pos = scrubberEl.getBoxQuads()[0].bounds.right;
+      let width = win.document.documentElement.offsetWidth;
+      if (pos >= width) {
+        setTimeout(resolve, 50);
+      } else {
+        setTimeout(check, 50);
+      }
+    }
+    check();
+  });
+}

new file mode 100644
--- /dev/null
+++ b/devtools/client/animationinspector/test/browser_animation_timeline_pause_button_03.js
@@ -0,0 +1,54 @@
+/* vim: set ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+requestLongerTimeout(2);
+
+// Also checks that the button goes to the right state when the scrubber has
+// reached the end of the timeline: continues to be in playing mode for infinite
+// animations, goes to paused mode otherwise.
+// And test that clicking the button once the scrubber has reached the end of
+// the timeline does the right thing.
+
+add_task(function* () {
+  yield addTab(URL_ROOT + "doc_simple_animation.html");
+
+  let {panel, inspector} = yield openAnimationInspector();
+  let timeline = panel.animationsTimelineComponent;
+  let btn = panel.playTimelineButtonEl;
+
+  // For a finite animation, once the scrubber reaches the end of the timeline, the pause
+  // button should go back to paused mode.
+  info("Select a finite animation and wait for the animation to complete");
+  yield selectNodeAndWaitForAnimations(".negative-delay", inspector);
+
+  let onScrubberStopped = waitForScrubberStopped(timeline);
+  // The page is reloaded to avoid missing the animation.
+  yield reloadTab(inspector);
+  yield onScrubberStopped;
+
+  ok(btn.classList.contains("paused"),
+     "The button is in paused state once finite animations are done");
+  yield assertScrubberMoving(panel, false);
+
+  info("Click again on the button to play the animation from the start again");
+  yield clickTimelinePlayPauseButton(panel);
+
+  ok(!btn.classList.contains("paused"),
+     "Clicking the button once finite animations are done should restart them");
+  yield assertScrubberMoving(panel, true);
+});
+
+function waitForScrubberStopped(timeline) {
+  return new Promise(resolve => {
+    timeline.on("timeline-data-changed",
+      function onTimelineData(e, {isMoving}) {
+        if (!isMoving) {
+          timeline.off("timeline-data-changed", onTimelineData);
+          resolve();
+        }
+      });
+  });
+}