NTP Update

[ryanml]

Fixes: https://github.com/brave/internal/issues/726

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Verified that these changes build without errors on
  • Android
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that these changes pass automated tests (unit, browser, security tests) on
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that all lint errors/warnings are resolved (npm run lint, npm run gn_check)
• Ran git rebase master (if needed).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Request a security/privacy review as needed.
• Add appropriate QA labels (QA/Yes or QA/No) to include the closed issue in milestone
• Public documentation has been updated as necessary. For instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Custom-Headers
  • https://github.com/brave/brave-browser/wiki/Web-compatibility-issues-with-tracking-protection
  • https://github.com/brave/brave-browser/wiki/QA-Guide

Test Plan:

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Request a security/privacy review as needed.
• Adequate test coverage exists to prevent regressions
• Verify test plan is specified in PR before merging to source

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on.
• All relevant documentation has been updated.

[bbondy]

I think the same type of things should be done for gemini and binance widgets but those ones should be done in a separate PR.

Adding @petemill for review of the front end files.

addressed changes

[petemill]

New validation code not working, sorry

[petemill]

nice 👍

changes addressed

[srirambv]

Verification passed on

Brave	1.17.7 Chromium: 86.0.4240.55 (Official Build) nightly (64-bit)
Revision	a6d625ef6f7fe8ea0675f1cf759155a05ee1be40-refs/branch-heads/4240@{#953}
OS	macOS Version 10.15.7 (Build 19H2)/ Linux/ Windows 10 OS Version 1809 (Build 17763.1457)

• Verified on a clean profile, opening NTP shows Bitcoin.com widget
  

• Verified by default the widget is stacked behind Binance widget
  

• Verified Bitcoin.com widget is available in Add cards settings and can be added or removed
  

• Verified default Fiat currency is set to EUR (EURO)
  

• Verified currency can be changed from default
  

• Verified amount only takes numerical/decimal values and doesn't accept any string input
  

• Verified clicking on the Buy button opens a landing page with the prepopulated value of the entered amount
  https://bitcoincom.moonpay.io/?currencyCode=ltc&baseCurrencyCode=aud&baseCurrencyAmount=100.53

• Verified clicking on Get the wallet here to get started opens up https://bitcoincom.moonpay.io/ landing page

• Verified New tab settings shows entry for Bitcoin.com
  

• Verified widget can be removed by clicking on the widget menu and selecting Hide Bitcoin.com

• Verified widget can be removed via dashboard settings

• Verified widget can be removed via new tab page settings

• Verified widget is available on all supported regions

• Verified widget is not shown for unsupported regions

• Verified clean profile on unsupported region and then switching to supported region doesn't add the widget

• Verified for supported regions on upgrade, widget is added to the stack automatically

Logged followup issues

• Dropdown should be able to capture keystrokes to quick select desired value [Widget] Dropdown should be able to capture keystrokes to quick select desired value brave-browser#11966
• Widget overflows from stack on certain locales [Widget] Widget overflows from stack on certain locales brave-browser#11965
• Missing translations for Bitcoin.com widget [Widget] Missing translations for Bitcoin.com widget brave-browser#11963
• Add messaging within widget when currency is below min value [Widget] Add messaging within widget when currency is below min value brave-browser#11960
• Dropdown should collapse on click [Widget] Dropdown should collapse on click brave-browser#11959
• Currency dropdown is broken [Widget] Currency dropdown is broken  brave-browser#11958