Bugzilla

**Affected versions**
* 65.0.1, 66.0b6, 66.0b11, 67.0a1 (2019-02-25)

**Affected platforms**
* Windows 10, macOS 10.13

**Steps to reproduce**
1. Launch Firefox, set it to Dark Theme;
2. Access https://mozilla.github.io/webrtc-landing/gum_test.html
3. Click on the Screen test;
4. Click on the Remmember this decision checkbox;

**Expected result**
* The string is readable;

**Actual result*
* Color theme setup makes it hard to read;

**Regression range**
* for the current regression range, the previous version had the panel's background color set to black ... which wasn't ideal either;
* First bad: 2018-04-09 17:33:45.385000
* Last good: 2018-04-09 17:07:57.689000
* Potential regressor: 1451947 

**Additional notes**
* attached screenshot with the issue;
* on Ubuntu the color is set to the default one;

**Affected versions**
* 65.0.1, 66.0b6, 66.0b11, 67.0a1 (2019-02-25)

**Affected platforms**
* Windows 10, macOS 10.13

**Steps to reproduce**
1. Launch Firefox, set it to Dark Theme;
2. Access https://mozilla.github.io/webrtc-landing/gum_test.html
3. Click on the Screen test;
4. Click on the Remmember this decision checkbox;

**Expected result**
* The string is readable;

**Actual result*
* Color theme setup makes it hard to read;

**Regression range**
* for the current regression range, the previous version had the panel's background color set to black ... which wasn't ideal either;
* First bad: 2018-04-09 17:33:45.385000
* Last good: 2018-04-09 17:07:57.689000
* Potential regressor: bug [1451947](https://bugzilla.mozilla.org/show_bug.cgi?id=1451947)

**Additional notes**
* attached screenshot with the issue;
* on Ubuntu the color is set to the default one;