Tab 'appear' animations run again when tab is moved

[petemill]

Test plan

#11501 (comment)

---

Description

Tab 'appear' animations run again when tab element is moved via a new sort order.

Steps to Reproduce

1. Create multiple tabs
2. Observe that the tab icon fades in with animation
3. Change tab order

Actual result:

• Observe that tabs that are moved have their icons fade in with animation again

Expected result:

• no fade-in animation

Reproduces how often: always

Brave Version

master, introduced in 33c5d10 for issue #10883 and PR

Test Plan

From PR #10691 / issue #10883 (create smooth transitions for tab components)

• close icon, favicon, private, new session icons will have a smooth transition when enabled
• audio icon will slightly scroll to the right when enabled

Resolving this issue

• Create multiple tabs with favicons
• Have a tab with audio playing and audio icon shown
• Move the tabs around, there should be no flicker off / fade-in of favicon or audio icon
• Repeat with tabs showing private icon, and session icon

[petemill]

Moved to milestone 0.22.x due to requiring it for a clean merge of #12565 and the same / similar test plan for that version.

[srirambv]

Verified on Windows x64

• 0.22.6 e6ff4ea
• libchromiumcontent: 65.0.3325.162
• muon: 5.1.0

Verified on macOS 10.12.6 x64 using the following build:

• 0.22.6 e6ff4ea
• libchromiumcontent: 65.0.3325.162
• muon: 5.1.0

Verified on Ubuntu 10.10 x64

• 0.22.7 8bb7e77
• libchromiumcontent: 65.0.3325.181
• muon: 5.1.1