[Chromium] Remove idbFactory from WebKitPlatformSupport
https://bugs.webkit.org/show_bug.cgi?id=106457

Reviewed by Adam Barth.

Now that https://codereview.chromium.org/12181010/ has landed, the
idbFactory method is no longer needed. (Embedders must now call
the new setIDBFactory method upon initialization.) Part of a
larger refactoring series; see tracking bug 82948.

* public/platform/WebKitPlatformSupport.h:
(WebKit):
* src/IDBFactoryBackendProxy.cpp:
(WebKit::IDBFactoryBackendProxy::IDBFactoryBackendProxy):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141896 268f45cc-cd09-0410-ab3c-d52691b4dbfc