Web Inspector: remove existing LayerTreeAgent protocol APIs
https://bugs.webkit.org/show_bug.cgi?id=111251

Source/WebCore:

In order to eventually provide a more useful API for the LayerTreeAgent
that will be done in followup bugs, we remove the current API exposed by
the agent providing a clean slate that will make future patches easier
to read. Additionally, we remove the "childLayers" property on the Layer
object since we will no longer be providing a hierarchy of layers, but
rather a flat list of layers attached to a node and its descendants.

No new tests since we're removing the APIs exposed by the LayerTreeAgent.
Subsequent patches will add tests as new APIs are added.

Reviewed by Timothy Hatcher.

* inspector/Inspector.json:
* inspector/InspectorDOMAgent.cpp:
* inspector/InspectorDOMAgent.h:
* inspector/InspectorLayerTreeAgent.cpp:
(WebCore::InspectorLayerTreeAgent::buildObjectForLayer):
* inspector/InspectorLayerTreeAgent.h:
(InspectorLayerTreeAgent):

LayoutTests:

Remove existing tests since they're testing API that we're
removing.

Reviewed by Timothy Hatcher.

* inspector-protocol/layer-tree-expected.txt: Removed.
* inspector-protocol/layer-tree-generated-content-expected.txt: Removed.
* inspector-protocol/layer-tree-generated-content.html: Removed.
* inspector-protocol/layer-tree.html: Removed.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@144624 268f45cc-cd09-0410-ab3c-d52691b4dbfc