MSE: Remove temporary layout test failure expectations

LayoutTests/TestExpectations

 
 # This test can't just be rebaselined because it has absolute file paths in the output.
 crbug.com/257132 http/tests/inspector/network/network-xhr-replay.html [ Failure ]
 
 crbug.com/258949 fast/filesystem/workers/file-writer-truncate-extend.html [ Failure Pass ]
 
 crbug.com/307782 [ Win ] http/tests/cache/stopped-revalidation.html [ Pass Timeout ]
 crbug.com/316146 [ XP ] http/tests/cache/cached-main-resource.html [ Pass Timeout ]
 
 # Transient - XHR mixed content type revert will be restored.
@@ skipping 483 matching lines @@
 crbug.com/282094 fast/repaint/video-mute-repaint.html [ Pass Timeout ]
 crbug.com/282095 storage/websql/read-transactions-running-concurrently.html [ Failure Pass ]
 crbug.com/318431 [ Linux ] fast/dom/shadow/transition-on-shadow-host-with-distributed-node.html [ Pass Timeout ]
 
 crbug.com/340206 [ Win ] http/tests/security/cross-origin-css.html [ Pass Timeout ]
 
 crbug.com/284734 svg/custom/getsvgdocument.html [ Pass ImageOnlyFailure ]
 
 crbug.com/283723 [ Win ] http/tests/local/fileapi/file-last-modified-after-delete.html [ Failure Pass Timeout ]
 
-# 351166 tracks changing Chromium implementation. These will Fail until Chromium-side (https://codereview.chromium.org/213253006/) lands.
-# 249422 tracks a subsequent changing Chromium implementation. These will Fail until Chromium-side (https://codereview.chromium.org/205703003/) lands.
-crbug.com/351166 crbug.com/249422 http/tests/media/media-source/mediasource-buffered.html [ Failure Pass ]
-crbug.com/351166 http/tests/media/media-source/webkitmediasource-append-in-ended-state.html [ Failure Pass ]
-crbug.com/351166 http/tests/media/media-source/webkitmediasource-zero-byte-append-in-ended-state.html [ Failure Pass ]
-crbug.com/249422 http/tests/media/media-source/mediasource-remove.html [ Failure Pass ]
-crbug.com/249422 http/tests/media/media-source/webkitmediasource-duration-changed.html [ Failure Pass ]
-
 # 309184 and 303419 track Android-specific failures
-# 249422 tracks a changing Chromium implementation that will cause failure until Chromium-side (https://codereview.chromium.org/205703003/) lands.
-crbug.com/309184 crbug.com/303419 crbug.com/284782 crbug.com/249422 http/tests/media/media-source/mediasource-duration.html [ Failure Pass ]
+crbug.com/309184 crbug.com/303419 crbug.com/284782 http/tests/media/media-source/mediasource-duration.html [ Failure Pass ]
 
 # 323284 tracks Android-specific flaky failure
 crbug.com/323284 crbug.com/324120 http/tests/media/media-source/webkitmediasource-removesourcebuffer-texttrack.html [ Pass Crash Failure ]
 
 crbug.com/323301 [ Android ] http/tests/media/media-source/mediasource-play-then-seek-back.html [ Pass Crash ]
 crbug.com/302729 [ Android ] http/tests/media/media-source/mediasource-seek-during-pending-seek.html [ Failure ]
-
-# 302729 tracks Android-specific failure
-# 249422 tracks a changing Chromium implementation that will cause failure until Chromium-side (https://codereview.chromium.org/205703003/) lands.
-crbug.com/302729 crbug.com/249422 http/tests/media/media-source/mediasource-seek-beyond-duration.html [ Failure Pass ]
+crbug.com/302729 [ Android ] http/tests/media/media-source/mediasource-seek-beyond-duration.html [ Failure ]
 
 crbug.com/286287 [ Linux Mac Android ] http/tests/inspector/network/network-initiator.html [ Failure Pass ]
 crbug.com/306228 [ Win ] http/tests/inspector/network/network-initiator.html [ Pass Failure Timeout ]
 
 # Pixel captures are currently totally broken on Android Nexus4's at the moment.
 crbug.com/293932 [ Android ] css1/formatting_model/horizontal_formatting.html [ Failure ]
 crbug.com/293932 [ Android ] fast/inspector-support/matchedrules.html [ ImageOnlyFailure ]
 crbug.com/293932 [ Android ] svg/W3C-SVG-1.1-SE/coords-dom-02-f.svg [ ImageOnlyFailure ]
 crbug.com/293932 [ Android ] svg/canvas/canvas-pattern-svg.html [ ImageOnlyFailure ]
 crbug.com/293932 [ Android ] css3/images/optimize-contrast-image.html [ ImageOnlyFailure Timeout Pass ]
@@ skipping 450 matching lines @@
 crbug.com/354791 [ Mac ] transitions/webkit-clip-path-equality.html [ Pass Failure ]
 crbug.com/354791 [ Mac ] virtual/threaded/transitions/webkit-clip-path-equality.html [ Pass Failure ]
 
 crbug.com/355459 [ Release ] inspector/elements/edit-dom-actions-shadow.html [ Pass Timeout ]
 
 crbug.com/355463 [ Linux Win ] css3/flexbox/repaint.html [ Pass Failure ]
 crbug.com/356957 [ Win Debug ] editing/spelling/spellcheck-editable-on-focus.html [ Pass Timeout ]
 crbug.com/355489 media/activation-behavior.html [ Pass Failure Timeout ]
 
 crbug.com/356148 media/audio-delete-while-slider-thumb-clicked.html [ Pass Crash ]