Initialize CursorData before Sandbox is enabled.

Initalizing Cursor Theme and loading images seem to result in system
calls which are not allowed under sandbox in GPU side. This Change
moves the initialation to happen during InitializeHardware call instead
of waiting till the Cursor is created. Eventually, we want to get rid of
all this and just use Cursor Images provided by Aura.

(cherry picked from commit 967c0eed0b55791b1c1514b11447669cad37ebaa)
DisplayPollThread: Handle EpollCreation calls during construction phase.

Currently, we do epoll_create calls when thread starts running. However,
GPU sandboxing has restrictions on these calls.  We move these calls to
construction phase which happens before Sandbox is enabled.

(cherry picked from commit b2f3e95e4a0a48a157bec7cb739b77831faec594)
Move XKB handling to BrowserProcess.

XKB Shared Memory initialization in GPU process was leading to some
restricted system calls. This patch moves XKB initialization and all
key handling to be done in EventHandler. Now, we have a separate event
to handle Virtual Key events and events coming from Hardware. After, this
CL one should be able to launch Chrome with Sandboxing enabled.

(cherry picked from commit 3401d983cd97beb3a0bc19d4e65a231f4d2e4f1f)

Conflicts:
	ui/events/event_converter_in_process.cc
	ui/events/event_converter_in_process.h
	ui/events/remote_event_dispatcher.h

Add missing files.

(cherry picked from commit cec6a375da33d3d4357f6e44cbbd0849fd30dc73)