UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/604.5.6 (KHTML, like Gecko) Version/11.0.3 Safari/604.5.6

Example URL:
any

Steps to reproduce the problem:
Two scenarios:
Scenario A.
1. Run a test using chromedriver with any mobile emulation configuration
2. Open devtools
3. And toggle device toolbar on
Scenario B.
1. Run a test using chromedriver with any mobile emulation configuration AND --auto-open-devtools-for-tabs
2. And toggle device toolbar on

What is the expected behavior?
Devtools detects the mobile emulation configuration and shows device toolbar with the actual test mobile emulation configuration 

What went wrong?
When chromedriver launch the browser without Devtools, upon launching it manually, the page is re-render. This is not an expected behaviour since the test have been launched with a mobile emulation with a specific form factor and devtools is not required to modified any single configuration if not explicitly asked for
Besides, since devtools is launched with device toolbar toggle off, when toggling it on, the page re-render again even with another screen size. 

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version:  Google Chrome	65.0.3325.162 (Official Build) (64-bit)  Channel: stable
OS Version: OS X 10.13.3
Flash Version:
 

Deleted: MobileEmulation_A1_NoDevtools.png 311 KB

	MobileEmulation_A1_NoDevtools.png 311 KB View Download

Deleted: MobileEmulation_A2_LaunchingDevtools.png 600 KB

	MobileEmulation_A2_LaunchingDevtools.png 600 KB View Download

Deleted: MobileEmulation_A3_DeviceToolbarOn.png 563 KB

	MobileEmulation_A3_DeviceToolbarOn.png 563 KB View Download

Deleted: MobileEmulation_B1_DeviceToolbarOff.png 496 KB

	MobileEmulation_B1_DeviceToolbarOff.png 496 KB View Download

Deleted: MobileEmulation_B2_DeviceToolbarOn.png 560 KB

	MobileEmulation_B2_DeviceToolbarOn.png 560 KB View Download