webtorrent page goes blank and displays "loading..." when switching to another application

[kjozwiak]

Description

When switching context from Brave to another application, you'll notice that the webtorrent page will go completely blank and will only display Loading..... Once you switch back to Brave as the active application, the entire screen is re-painted.

Steps to Reproduce

1. launch either the latest beta or dev
2. load https://webtorrent.io/torrents/big-buck-bunny.torrent in a new tab
3. open Chrome and start switching back and forth between Chrome & Brave

You'll notice once you switch over to Chrome, the entire webtorrent page goes blank with only Loading.. appearing.

Actual result:

Expected result:

When switching between Brave and other applications, the webtorrent tab shouldn't go completely blank and display Loading...

Reproduces how often:

100% reproducible using the above STR.

Brave version (chrome://version info)

Brave	0.55.10 Chromium: 70.0.3538.22 (Official Build) beta(64-bit)
Revision	ac9418ba9c3bd7f6baaffa0b055dfe147e0f8364-refs/branch-heads/3538@{#468}
OS	Mac OS X

Reproducible on current release:

• Does it reproduce on brave-browser dev/beta builds?

Currently reproducible on both dev and beta builds.

Brave	0.56.1 Chromium: 70.0.3538.22 (Official Build) dev (64-bit)
Revision	ac9418ba9c3bd7f6baaffa0b055dfe147e0f8364-refs/branch-heads/3538@{#468}
OS	Mac OS X

• Does it reproduce on browser-laptop?

Nope, this isn't reproducible under 0.24.0 which is the current muon live build.

Additional Information

• @srirambv couldn't reproduce this under Win 10
• @btlechowski couldn't reproduce this under Win 7
• @LaurenWags also managed to reproduce this on macOS 10.12.6

[LaurenWags]

Verified passed on macOS x64 10.12.6

Brave	0.56.7 Chromium: 70.0.3538.77 (Official Build) beta(64-bit)
Revision	0f6ce0b0cd63a12cb4eccea3637b1bc9a29148d9-refs/branch-heads/3538@{#1039}
OS	Mac OS X

• Verified STR from description
  cc @kjozwiak to verify on his macOS version as well

Went through verification using the following build under macOS 10.13.6 x64 - PASSED

Brave	0.56.7 Chromium: 70.0.3538.77 (Official Build) beta(64-bit)
Revision	0f6ce0b0cd63a12cb4eccea3637b1bc9a29148d9-refs/branch-heads/3538@{#1039}
OS	Mac OS X

Verification Passed on

Brave	0.56.8 Chromium: 70.0.3538.77 (Official Build) (64-bit)
Revision	0f6ce0b0cd63a12cb4eccea3637b1bc9a29148d9-refs/branch-heads/3538@{#1039}
OS	Linux

Verification passed on

Brave	0.56.8 Chromium: 70.0.3538.77 (Official Build) (64-bit)
Revision	0f6ce0b0cd63a12cb4eccea3637b1bc9a29148d9-refs/branch-heads/3538@{#1039}
OS	Windows

• Verified the STR mentioned in description