First pass cleanup CL: https://codereview.chromium.org/2696033003/

CL1: https://codereview.chromium.org/2789253002/

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5360eea373d896d8916087952ace99ed2a7ff05a

commit 5360eea373d896d8916087952ace99ed2a7ff05a
Author: tdanderson <tdanderson@chromium.org>
Date: Mon Apr 03 21:17:32 2017

[Ash] Remove HoverHighlightView::hover()

As part of the material design rework of the system menu,
the |hover_| member of HoverHighlightView was no longer
being updated. However both the network submenu and the
VPN submenu were accessing this member (via hover()) to
keep currently-hovered menu rows visible during an update
to the network/VPN list. Remove hover() and instead call
View::IsMouseHovered() at its call sites instead to
restore the intended behavior.

BUG= 686345 
TEST=manual

Review-Url: https://codereview.chromium.org/2789253002
Cr-Commit-Position: refs/heads/master@{#461543}

[modify] https://crrev.com/5360eea373d896d8916087952ace99ed2a7ff05a/ash/common/system/chromeos/network/network_list_delegate.h
[modify] https://crrev.com/5360eea373d896d8916087952ace99ed2a7ff05a/ash/common/system/chromeos/network/network_list_md.cc
[modify] https://crrev.com/5360eea373d896d8916087952ace99ed2a7ff05a/ash/common/system/chromeos/network/network_state_list_detailed_view.cc
[modify] https://crrev.com/5360eea373d896d8916087952ace99ed2a7ff05a/ash/common/system/chromeos/network/network_state_list_detailed_view.h
[modify] https://crrev.com/5360eea373d896d8916087952ace99ed2a7ff05a/ash/common/system/chromeos/network/vpn_list_view.cc
[modify] https://crrev.com/5360eea373d896d8916087952ace99ed2a7ff05a/ash/common/system/tray/hover_highlight_view.h

Remove mention of MaterialDesignController, perform preliminary cleanup: https://codereview.chromium.org/2795143005/

Further code cleanup tracked in  issue 708190 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5

commit 889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5
Author: tdanderson <tdanderson@chromium.org>
Date: Wed Apr 05 14:30:37 2017

[Ash] Remove pre-MD code paths from HoverHighlightView

This CL removes all mention of ash::MaterialDesignController
from the HoverHighlightView class and performs some
preliminary cleanup of dead code. Further refactoring
and code cleanup for this class requires some additional
investigation and is tracked by  crbug.com/708190 .

BUG= 686345 
TEST=manual

Review-Url: https://codereview.chromium.org/2795143005
Cr-Commit-Position: refs/heads/master@{#462064}

[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/chromeos/audio/audio_detailed_view.cc
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/chromeos/bluetooth/tray_bluetooth.cc
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/chromeos/cast/tray_cast.cc
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/chromeos/ime_menu/ime_list_view.cc
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/chromeos/network/network_info.h
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/chromeos/network/network_state_list_detailed_view.cc
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/chromeos/network/vpn_list_view.cc
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/chromeos/palette/common_palette_tool.cc
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/tray/hover_highlight_view.cc
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/tray/hover_highlight_view.h
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/tray/label_tray_view.cc
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/tray/tray_constants.cc
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/tray/tray_constants.h
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/tray_accessibility.cc
[modify] https://crrev.com/889fe85b1ec6deaef84f7c1b3a186aa0a7a3f7f5/ash/common/system/tray_accessibility.h