fix(card): Use on-surface color for action icons

[kfranqueiro]

Fixes #4238.

[mdc-web-bot]

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Screenshot test report 🚦

3 screenshots changed from master on commit 7ce5207:

• https://storage.googleapis.com/mdc-web-screenshot-tests/travis/2019/03/19/20_36_24_376/report/report.html?utm_source=github&utm_medium=pr_comment

Details

3 Changed:

• spec/mdc-card/classes/media.html

[kfranqueiro]

I checked with design on this while I was asking about #4520, and this should be on-surface with 87% opacity (high emphasis).

[mdc-web-bot]

🤖 Beep boop!

Screenshot test report 🚦

3 screenshots changed from master on commit f61e457:

• https://storage.googleapis.com/mdc-web-screenshot-tests/travis/2019/03/19/21_39_25_055/report/report.html?utm_source=github&utm_medium=pr_comment

Details

3 Changed:

• spec/mdc-card/classes/media.html

[mdc-web-bot]

🤖 Beep boop!

Screenshot test report 🚦

3 screenshots changed from master on commit f61e457:

• https://storage.googleapis.com/mdc-web-screenshot-tests/travis/2019/03/20/15_32_44_897/report/report.html?utm_source=github&utm_medium=pr_comment

Details

3 Changed:

• spec/mdc-card/classes/media.html

[abhiomkar]

LGTM.

[mdc-web-bot]

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Screenshot test report 🚦

3 screenshots changed from master on commit 79bb8a4:

• https://storage.googleapis.com/mdc-web-screenshot-tests/travis/2019/03/25/22_10_04_982/report/report.html?utm_source=github&utm_medium=pr_comment

Details

3 Changed:

• spec/mdc-card/classes/media.html