The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6bee4affb2c282fafcfecd015e207826ee69be59

commit 6bee4affb2c282fafcfecd015e207826ee69be59
Author: Bret Sepulveda <bsep@chromium.org>
Date: Thu May 10 22:21:54 2018

Refactor GlassBrowserFrameView to use GetFrameColor.

GlassBrowserFrameView had a GetTitlebarColor method that was redundant
with BrowserNonClientFrameView::GetFrameColor, so this patch
deduplicates them.

Bug:  841643 
Change-Id: If1f0b3724fac814b8b445c1792213753b49e2eda
Reviewed-on: https://chromium-review.googlesource.com/1053490
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Reviewed-by: Peter Boström <pbos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557693}
[modify] https://crrev.com/6bee4affb2c282fafcfecd015e207826ee69be59/chrome/browser/ui/views/frame/glass_browser_frame_view.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/46bf2d1ec108aeb8b3a9b6c09d91fd1fb4d48e96

commit 46bf2d1ec108aeb8b3a9b6c09d91fd1fb4d48e96
Author: Bret Sepulveda <bsep@chromium.org>
Date: Mon May 14 22:15:18 2018

First pass on single-tab mode for Refresh.

This patch adds the basic frame color change, protected by the Refresh
flag. When the user has a single tab and no theme frame image, the frame
will paint the same color as the active tab (effectively hiding it).
Otherwise the behavior is the same as before.

This patch does not hide the tab close button or do any animation.

Bug:  841643 
Change-Id: I62a797ffeee39b9f2646151d0ba224f21e7f0e04
Reviewed-on: https://chromium-review.googlesource.com/1054580
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558489}
[modify] https://crrev.com/46bf2d1ec108aeb8b3a9b6c09d91fd1fb4d48e96/chrome/browser/ui/views/frame/browser_non_client_frame_view.cc
[modify] https://crrev.com/46bf2d1ec108aeb8b3a9b6c09d91fd1fb4d48e96/chrome/browser/ui/views/frame/browser_non_client_frame_view.h
[modify] https://crrev.com/46bf2d1ec108aeb8b3a9b6c09d91fd1fb4d48e96/chrome/browser/ui/views/frame/browser_non_client_frame_view_mus.cc
[modify] https://crrev.com/46bf2d1ec108aeb8b3a9b6c09d91fd1fb4d48e96/chrome/browser/ui/views/frame/browser_non_client_frame_view_mus.h
[modify] https://crrev.com/46bf2d1ec108aeb8b3a9b6c09d91fd1fb4d48e96/chrome/browser/ui/views/frame/glass_browser_frame_view.cc
[modify] https://crrev.com/46bf2d1ec108aeb8b3a9b6c09d91fd1fb4d48e96/chrome/browser/ui/views/frame/glass_browser_frame_view.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/902a007c74f8242b1fffb27b322a9cdc75302ead

commit 902a007c74f8242b1fffb27b322a9cdc75302ead
Author: Bret Sepulveda <bsep@chromium.org>
Date: Thu May 31 00:13:32 2018

Fix single tab mode damage being incorrect after uninstalling a theme.

When BrowserNonClientFrameView is destroyed and recreated, for example
when the user installs or uninstalls a theme, the BrowserView is reused.
But the Tabstrip was only being observed on BrowserView creation.

This is probably a very old bug, but it's hard to observe the effects
without single tab mode. In particular, I found that the profile
switcher chip can get out of sync with the size of the tabstrip and
overlap the new tab button, which is also fixed.

Bug:  841643 
Change-Id: Ia3c20a70f8082e1a8b90d34da35011313c344035
Reviewed-on: https://chromium-review.googlesource.com/1079958
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#563080}
[modify] https://crrev.com/902a007c74f8242b1fffb27b322a9cdc75302ead/chrome/browser/ui/views/frame/browser_non_client_frame_view.cc
[modify] https://crrev.com/902a007c74f8242b1fffb27b322a9cdc75302ead/chrome/browser/ui/views/frame/browser_non_client_frame_view.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/53bcedc89c74ba2ea38c60a2291a6679093b79c6

commit 53bcedc89c74ba2ea38c60a2291a6679093b79c6
Author: Bret Sepulveda <bsep@chromium.org>
Date: Thu May 31 01:28:42 2018

Hide the tab's close-x in Refresh's single-tab mode.

This patch refactors the single tab mode to be tracked by the tabstrip,
and enabled/disabled by BrowserNonClientFrameView when appropriate. The
tabstrip uses that mode flag to force the close-x for the active tab to
be invisible.

Bug:  841643 
Change-Id: I0c8713e5190af935d665e7d10f984db8624b4ab0
Reviewed-on: https://chromium-review.googlesource.com/1068214
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#563109}
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/frame/browser_non_client_frame_view.cc
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/frame/browser_non_client_frame_view.h
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/tabs/browser_tab_strip_controller.cc
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/tabs/browser_tab_strip_controller.h
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/tabs/fake_base_tab_strip_controller.cc
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/tabs/fake_base_tab_strip_controller.h
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/tabs/tab.cc
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/tabs/tab.h
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/tabs/tab_controller.h
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/tabs/tab_strip.cc
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/tabs/tab_strip.h
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/tabs/tab_strip_controller.h
[modify] https://crrev.com/53bcedc89c74ba2ea38c60a2291a6679093b79c6/chrome/browser/ui/views/tabs/tab_unittest.cc

Triage notes: We need to file a new P1 bug for new single tab spec, downgrade this to P2 and mark new bug as a blocker. 

I filed new bugs for the outstanding issues that I'm aware need to be addressed for single-tab mode.  This bug is effectively just a tracking bug now.  Downgrading to P2 per comment 5, though personally I'd downgrade to P3.

Moving meta bugs to PM to make eng bandwidth more clear.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4f891da68185eea0e9e20a7c31e428fd1dcdb215

commit 4f891da68185eea0e9e20a7c31e428fd1dcdb215
Author: Bret Sepulveda <bsep@chromium.org>
Date: Mon Jul 16 19:10:30 2018

Add feature flag for single-tab mode and disable it by default.

Bug:  841643 
Change-Id: I28d6ec0af4aa8ad77eeb9e140a3dac58097002ea
Reviewed-on: https://chromium-review.googlesource.com/1136064
Reviewed-by: Robert Liao <robliao@chromium.org>
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575375}
[modify] https://crrev.com/4f891da68185eea0e9e20a7c31e428fd1dcdb215/chrome/browser/about_flags.cc
[modify] https://crrev.com/4f891da68185eea0e9e20a7c31e428fd1dcdb215/chrome/browser/flag_descriptions.cc
[modify] https://crrev.com/4f891da68185eea0e9e20a7c31e428fd1dcdb215/chrome/browser/flag_descriptions.h
[modify] https://crrev.com/4f891da68185eea0e9e20a7c31e428fd1dcdb215/chrome/browser/ui/views/frame/browser_non_client_frame_view.cc
[modify] https://crrev.com/4f891da68185eea0e9e20a7c31e428fd1dcdb215/chrome/common/chrome_features.cc
[modify] https://crrev.com/4f891da68185eea0e9e20a7c31e428fd1dcdb215/chrome/common/chrome_features.h
[modify] https://crrev.com/4f891da68185eea0e9e20a7c31e428fd1dcdb215/tools/metrics/histograms/enums.xml

Closing all Single-Tab Mode bugs as we pursue a new direction in this area.