UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36

Steps to reproduce the problem:
1. Get a Dell Vostro 3560 laptop. Note that this has two video cards:

00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Thames [Radeon HD 7500M/7600M Series] (rev ff)

2. Upgrade it to fedora 26

What is the expected behavior?
Scrolling is fast. chrome:///gpu says that all hardware acceleration acceleration is disabled because the ATI driver is too old:

ATI/AMD cards with older drivers in Linux are crash-prone: 71381, 76428, 73910, 101225, 136240, 357314
Disabled Features: flash_stage3d, gpu_compositing, panel_fitting, flash3d, gpu_rasterization, accelerated_2d_canvas, accelerated_video_decode, webgl2, accelerated_webgl, flash_stage3d_baseline, accelerated_video_encode

However, it isn't too old:

$ rpm -q xorg-x11-drv-ati-7.9.0-1.fc26.x86_64
xorg-x11-drv-ati-7.9.0-1.fc26.x86_64
$ rpm -qa mesa-dri-drivers
mesa-dri-drivers-17.1.7-1.fc26.i686
mesa-dri-drivers-17.1.7-1.fc26.x86_64

With --ignore-gpu-blacklist, chrome:///gpu has:

GPU0	VENDOR = 0x1002, DEVICE= 0x6840
GPU1	VENDOR = 0x8086, DEVICE= 0x0166 *ACTIVE*
Optimus	false
Optimus	false
AMD switchable	true
Driver vendor	Mesa
Driver version	17.1.7
Driver date	
Pixel shader version	4.20
Vertex shader version	4.20
Max. MSAA samples	8
Machine model name	
Machine model version	
GL_VENDOR	Intel Open Source Technology Center
GL_RENDERER	Mesa DRI Intel(R) Ivybridge Mobile
GL_VERSION	4.2 (Core Profile) Mesa 17.1.7

which is newer than the blacklisted version (https://src.chromium.org/viewvc/chrome/trunk/src/gpu/config/software_rendering_list_json.cc#l74)

I've attached the glxinfo output.

Using --ignore-gpu-blacklist improves performance again

What went wrong?
Noticeable lag in scrolling performance, which seems to be due to GPU acceleration being disabled

Did this work before? Yes 

Chrome version: 60.0.3112.113  Channel: stable
OS Version: Fedora 26
Flash Version: 

I'm not 100% sure that GPU acceleration was used before; its possible that it wasn't and this is a performance regression in the software rendering path. I sent crash bea906c130000000 back in April so maybe that has enough debug info to see?
 

Deleted: glxinfo.txt 25.3 KB

glxinfo.txt 25.3 KB View Download