Full custom preview generation is moved to custom-preview file
including frontend part. New custom preview implementation returns
body getter function instead of bind function, formatter and config
objects. Body getter function calls formatter.body(object, config)
and returns json ML.

R=dgozman@chromium.org

Bug: chromium:595206
Cq-Include-Trybots: luci.chromium.try:linux_chromium_headless_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I14ff3d8abb4a47d2bbc2e6eaa1835fc362ac7369
Reviewed-on: https://chromium-review.googlesource.com/c/1292686
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56872}

This reverts commit 003159e7.

Reason for revert: breaks roll into Chromium: https://ci.chromium.org/p/chromium/builders/luci.chromium.try/linux_chromium_headless_rel/3140

Original change's description:
> [inspector] RemoteObject.description should be empty for primitive type
> 
> We currently report description field for numbers. On client side user
> can calculate description as remoteObject.unserializableValue ||
> (remoteObject.value + ''). Let's report description only for objects to
> simplify value -> remoteObject logic a bit.
> 
> R=​dgozman@chromium.org
> TBR=jgruber@chromium.org
> 
> Bug: chromium:595206
> Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
> Change-Id: I91356a44aa3024e20c8f966869abf4a41b88e4bc
> Reviewed-on: https://chromium-review.googlesource.com/737485
> Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
> Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#53453}

TBR=dgozman@chromium.org,pfeldman@chromium.org,kozyatinskiy@chromium.org

Change-Id: Ifc184e1ac158d9ea7034922a7250444448fac49f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:595206
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Reviewed-on: https://chromium-review.googlesource.com/1081207Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Commit-Queue: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53461}

We currently report description field for numbers. On client side user
can calculate description as remoteObject.unserializableValue ||
(remoteObject.value + ''). Let's report description only for objects to
simplify value -> remoteObject logic a bit.

R=dgozman@chromium.org
TBR=jgruber@chromium.org

Bug: chromium:595206
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I91356a44aa3024e20c8f966869abf4a41b88e4bc
Reviewed-on: https://chromium-review.googlesource.com/737485
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53453}

This method enables test of agent::restore methods.
Bonus: forbid setCustomObjectFormatterEnabled on disabled agent.

BUG=none
R=dgozman@chromium.org

Review-Url: https://codereview.chromium.org/2713023004
Cr-Commit-Position: refs/heads/master@{#43502}