Routing to Collin for Inactive/Active states.

I'm working this out (and crbug.com/859243) with bettes@ soon. I'll post as soon as I have an update.

I'm also adding Windows as an affected OS because the colors are the same (I think?)

I don't think Windows is the same.

I think at least some, if not all, of those Linux colors are system-theme-provided.  You should talk to Tom Anderson.

It looks like the classic theme is being used, based on the screenshots provided.  This means the colors are not provided by the system theme.

I think we want the classic theme on Linux to be using the same colors as the default theme that we use on Windows and Mac.

The colors may be a little different (even if they're not supposed to be), but the same problem exists on Windows: not much contrast between the active an inactive Chrome windows. 

Unless my memory of the change we checked in recently on this is poor, the active and inactive windows on Windows contrast quite a bit more than that screenshot.  That said, on Win 10 at least we're not _supposed_ to use title bar color to contrast active with inactive windows (unless colored titlebars are enabled, in which case we comply with them); what we're doing violates the platform standard.

Here's the difference between the active and inactive window on Win10.

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Agree that we're doing better on Windows 10 than on Linux's classic theme. 

>> from c4: I think we want the classic theme on Linux to be using the same colors as the default theme that we use on Windows and Mac.

I think that's a correct assumption, but what's the precedent on Linux regarding changing the classic theme?

Hm.. it looks like the Linux classic theme colors are already the same as the default theme on Windows (the colors in the original post are the same as the colors in c#7).

Agreed, the one thing Win10 has going for it is the active window shadow and the blue highlight around the window.

Apparently my memory was indeed poor...

The problem also occurs on Linux when using the GTK+ theme. I would expect the background of the tab strip to be blue, per the active window color of my GTK theme. (I believe this used to be the case; I'm not sure when it changed.)

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The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9e28801fa50b407400a396699b7618badd4e5d47

commit 9e28801fa50b407400a396699b7618badd4e5d47
Author: Collin Baker <collinbaker@chromium.org>
Date: Fri Nov 09 00:40:36 2018

Update tab text colors

This updates tab text colors to both enhance contrast of text over tab
backgrounds as well as contrast between active and inactive windows.

Bug: 859243, 881916
Change-Id: I98257077fd6a9b7cf9521f845ea40218dcf11a70
Reviewed-on: https://chromium-review.googlesource.com/c/1297185
Commit-Queue: Collin Baker <collinbaker@chromium.org>
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Reviewed-by: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606668}
[modify] https://crrev.com/9e28801fa50b407400a396699b7618badd4e5d47/chrome/browser/ui/views/frame/browser_non_client_frame_view.cc

***Mass UI Triage***

jamescook@ could you please help in verifying the issue?

Hmm. The colors did change, but I still don't think the difference is obvious enough. See new screenshot.

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	Screenshot from 2018-11-26 11-21-52.png 428 KB View Download

BTW, Windows 10 indicates this by setting the alpha of things like caption buttons in inactive windows to 40%.  Chrome is currently doing 75%.  So one way we could increase differentiation here (at the cost of legibility of titles in background windows, but that's also the tradeoff the native OS makes) is to go to 40%.