[Desktop] SpeedReader communicate from rewriting library when no content found

[AndriusA]

Description

SpeedReader currently falls back to normal page rendering if no content is found as defined by having less than a threshold (500) bytes in the output buffer. This is potentially fragile because there might be more boilerplate content than that.

Steps to Reproduce

N/A

Actual result:

Hardcoded threshold value

Expected result:

Should propagate information on whether there was any content matching content rules from rewriting library back to url loader.

Reproduces how often:

N/A

Brave version (brave://version info)

Brave	1.12.14 Chromium: 83.0.4103.97 (Official Build) nightly (64-bit)
Revision	326d148b9655369b86498d9ecca39f63dd2bdd2d-refs/branch-heads/4103@{#657}
OS	macOS Version 10.15.4 (Build 19E287)

Version/Channel Information:

• Can you reproduce this issue with the current release? N/A
• Can you reproduce this issue with the beta channel? N/A
• Can you reproduce this issue with the dev channel? N/A
• Can you reproduce this issue with the nightly channel? N/A

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? N/A
• Does the issue resolve itself when disabling Brave Rewards? N/A
• Is the issue reproducible on the latest version of Chrome? N/A

Miscellaneous Information:

[iefremov]

stale