Move handle encoding functions to their respective implementation files
https://bugs.webkit.org/show_bug.cgi?id=139957

Reviewed by Dan Bernstein.

* Shared/API/APIFrameHandle.cpp:
(API::FrameHandle::encode):
(API::FrameHandle::decode):
* Shared/API/APIFrameHandle.h:
* Shared/API/APIPageGroupHandle.cpp:
(API::PageGroupHandle::PageGroupHandle):
(API::PageGroupHandle::encode):
(API::PageGroupHandle::decode):
* Shared/API/APIPageGroupHandle.h:
* Shared/API/APIPageHandle.cpp:
(API::PageHandle::encode):
(API::PageHandle::decode):
* Shared/API/APIPageHandle.h:
* Shared/UserData.cpp:
(WebKit::UserData::encode):
(WebKit::UserData::decode):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@177749 268f45cc-cd09-0410-ab3c-d52691b4dbfc