Add Dapp detection

[bbondy]

We should give a notification prompt to ask the user to install MetaMask if they visit a Dapp like cryptokitties.

See:
https://github.com/brave/browser-laptop/blob/master/app/browser/reducers/dappReducer.js

Test plan

• With a new profile, go to cryptokitties.co and you should see a prompt to install from the website.
• After it is installed, you should not get this prompt anymore.
• You should not see this prompt on a new profile on other sites.

[lukemulks]

Would it be possible for us to preload MetaMask, as we do with b-l?

We provided a security and blockchain advantage in the market when we shipped with MM pre-installed (and inactive).

Recalling when the extension store recently removed the legit MM along with some duplicates - Brave had the advantage and benefit of being able to confirm to our user base (and the public) that our pre-loaded MM extension was authentic and up to date.

Also allows for Brave to state that we ship a web3-ready browser.

There may be some reason I'm unaware of why it's better not to do this, but mentioning as I found myself looking for MM in the dev channel.

[bbondy]

We never pre-installed metamask, but we just made it really easy to install via the Dapp detection and by having an option directly in settings to download and install it in 1 step.

[bsclifton]

When looking at this, please see this issue regarding the integration done with the Muon version of Brave:
brave/browser-laptop#15221

[simonhong]

Sub tasks

• Add Dapp detection preference in settings (If it is enabled brave extension notifies to browser)
• Implement extension for detecting whether webpage is Dapp (trying to access window.web3) Reuse brave extension for detection
• Implement extension API
  • braveShield.dappAvailable for notifying to browser from detecting extension when extension thinks current page is Dapp
  • braveShield.dappDetectionEnabled
• Implement UI (by using permission request infra) for notifying to user about this page is Dapp and guiding to install our wallet extension(fork of MetaMask).

[tildelowengrimm]

@simonhong we're currently developing a separate cryptocurrency wallet based on MetaMask. The Ðapp-detection should be integrated with that rather than prompting for a separate MetaMask install.

[simonhong]

@tomlowenthal Yup, modified (I know that but forgot to mention about it) :)

[bsclifton]

@bbondy could you put together a quick test plan? 😄

[bbondy]

added test plan

[kjozwiak]

Verification PASSED on macOS 10.14.6 x64 using the following build:

Brave	0.69.132 Chromium: 77.0.3865.90 (Official Build) (64-bit)
Revision	58c425ba843df2918d9d4b409331972646c393dd-refs/branch-heads/3865@{#830}
OS	macOS Version 10.14.6 (Build 18G95)

• Verified STR/Cases outlined under Add Dapp detection #718 (comment)
• Verified STR/Cases outlined under web3 prompt/modal appearing for sites that don't have web3 integrated #6238 (comment)

Verification passed on

Brave	0.69.132 Chromium: 77.0.3865.90 (Official Build) (64-bit)
Revision	58c425ba843df2918d9d4b409331972646c393dd-refs/branch-heads/3865@{#830}
OS	Ubuntu 18.04 LTS

• Verified STR/Cases outlined under Add Dapp detection #718 (comment)
• Verified STR/Cases outlined under web3 prompt/modal appearing for sites that don't have web3 integrated #6238 (comment)

Verification passed on

Brave	0.69.132 Chromium: 77.0.3865.90 (Official Build) (64-bit)
Revision	58c425ba843df2918d9d4b409331972646c393dd-refs/branch-heads/3865@{#830}
OS	Windows 10 OS Version 1803 (Build 17134.1006)

• Verified STR/Cases outlined under Add Dapp detection #718 (comment)
• Verified STR/Cases outlined under web3 prompt/modal appearing for sites that don't have web3 integrated #6238 (comment)

[tmcw]

Because my previous bug got folded into this one, let me summarize:

Detecting 'Installing a Crypto Wallet' by using a getter on window.web3 is inaccurate and misleading to users. For sites like ours, we want to keep track of globals, and something as simple as

Object.getOwnPropertyNames(window).forEach(key => window[key])

Triggers this message, which recurs even if a user clicks 'Deny'. It's a product that has nothing to do with crypto and this message is incorrect at least and a problem for user trust.

You could:

• Make the property non-enumerable
• Drop this check

Or something else. For now we'll have to hardcode a workaround into our app to make it avoid web3.

[srirambv]

@tmcw your previous issue was on muon (legacy browser) Would you mind adding a new issue and we can have that triaged.