[RemotePlayback] Added IDL harness WebPlatform test for RemotePlayback API.

third_party/WebKit/LayoutTests/W3CImportExpectations

 # This file controls which subdirectories of the w3c test repos we import.
 #
 # This file acts as a blacklist; directories and files not listed here will
 # automatically be found and imported.
 #
 # This file is read by webkitpy/w3c/directory_owners_extractor.py to decide who
 # to contact for new failures; it will read entries with the following format:
 # When removing blacklist entries:
 # * Comment out the line rather than deleting it, to show it is intentional.
 # * Change [ Skip ] to [ Pass ]
@@ skipping 312 matching lines @@
 ## Owners: nzolghadr@chromium.org,mustaq@chromium.org
 # external/wpt/pointerevents [ Pass ]
 ## Owners: chongz@chromium.org
 # external/wpt/pointerlock [ Pass ]
 external/wpt/presentation-api [ Skip ]
 external/wpt/progress-events [ Skip ]
 external/wpt/proximity [ Skip ]
 ## Owners: rob.buis@samsung.com
 # external/wpt/quirks-mode [ Pass ]
 ## Owners: avayvod@chromium.org,mlamouri@chromium.org
-# external/wpt/remote-playback [ Pass ]
+external/wpt/remote-playback [ Pass ]

[foolip, 2017/05/08 14:58:03]

This should actually be commented out. The weirdness is documented at the top of
this file, and I've filed crbug.com/713987 to get everything except the skip
lines out of this file.

 ## Owners: jochen@chromium.org,estark@chromium.org
 # external/wpt/referrer-policy [ Pass ]
 external/wpt/resource-timing [ Skip ]
 ## Owners: jsbell@chromium.org
 # external/wpt/resources [ Pass ]
 external/wpt/resources/docs [ Skip ]
 external/wpt/resources/examples [ Skip ]
 external/wpt/resources/webidl2/README.md [ Skip ]
 external/wpt/resources/webidl2/test [ Skip ]
 external/wpt/screen-orientation [ Skip ]
@@ skipping 395 matching lines @@
 external/wpt/uievents/order-of-events/mouse-events/click-on-html-manual.html [ Skip ]
 external/wpt/uievents/order-of-events/mouse-events/click-order-manual.html [ Skip ]
 external/wpt/uievents/order-of-events/mouse-events/mouseevents-mousemove-manual.htm [ Skip ]
 external/wpt/uievents/order-of-events/mouse-events/mousemove-across-manual.html [ Skip ]
 external/wpt/uievents/order-of-events/mouse-events/mousemove-between-manual.html [ Skip ]
 external/wpt/keyboard-lock/idlharness.https.html [ Skip ]
 external/wpt/keyboard-lock/navigator-cancelKeyboardLock.https.html [ Skip ]
 external/wpt/keyboard-lock/navigator-requestKeyboardLock.https.html [ Skip ]
 external/wpt/keyboard-lock/navigator-requestKeyboardLock-two-parallel-requests.https.html [ Skip ]
 external/wpt/keyboard-lock/navigator-requestKeyboardLock-two-sequential-requests.https.html [ Skip ]