Resolve name conflict between regular and cocoa classes

When building using jumbo, files may end up in the same scope.
In chrome/browser/ui, ui elements defined with the same name in
both browser/ui and  browser/ui/cocoa conflict. This is relevant
for the classes:

HoverButton
ReloadButton
TabStripController
TabController
NewTabButton
BookmarkBarView
DownloadShelfViewCocoa
ToolbarButton
AvatarButton
SadTabView
AlertIndicatorButton
ToolbarView

This commit solves the issue by adding "Cocoa" to the classes
defined in chrome/browser/ui/cocoa. This is changed in
chrome/browser/ui/cocoa and ui/base/cocoa.

Bug: 803406
Change-Id: Iafd3b9447e4ed6960d86d43d12213ad367919357
Reviewed-on: https://chromium-review.googlesource.com/1140055
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Oscar Johansson <oscarj@opera.com>
Cr-Commit-Position: refs/heads/master@{#575959}
85 files changed