Disable indexedDB support if a SecurityError is thrown

[gikrauss]

When using Shaka player inside an cross domain iframe in Firefox with 3rd party cookies blocked, probeSupport method throws a SecurityError.

The error is thrown in lib/offline/indexeddb/storage_mechanism.js:340, when accessing window.indexedDB.

The proposed solution removes window.indexedDB with a polyfill, using the same approach implemented for Chromecast.

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[gikrauss]

@googlebot I signed it!

[googlebot]

CLAs look good, thanks!

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[joeyparrish]

Thank you so much for your contribution!

[joeyparrish]

Thank you so much for your contribution!

[shaka-bot]

Test Failure:

Generating Closure dependencies...
Linting JavaScript...

/var/lib/jenkins/workspace/Manual PR Test (local-tests)/lib/polyfill/indexed_db.js
44:13  error  Unexpected negating the left operand of 'instanceof' operator  no-unsafe-negation

✖ 1 problem (1 error, 0 warnings)
1 error and 0 warnings potentially fixable with the `--fix` option.

END-BUILD: FAILURE
Build step 'Execute shell' marked build as failure

[joeyparrish]

Looks good to me. Thanks! I'll run it through the build bot once more.

[shaka-bot]

Test Failure:

Generating Closure dependencies...
Linting JavaScript...
Linting CSS...
Linting HTML...

Config loaded: /var/lib/jenkins/workspace/Manual PR Test (local-tests)/.htmlhintrc

Config loaded: /var/lib/jenkins/workspace/Manual PR Test (local-tests)/.htmlhintrc

Config loaded: /var/lib/jenkins/workspace/Manual PR Test (local-tests)/.htmlhintrc

Scanned 3 files, no errors found (49 ms).
Checking that the build files are complete...
Checking for common misspellings...
Checking correct usage of eslint-disable...
Checking the tests for type errors...
No changes detected, skipping. Use --force to override.
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.google.protobuf.UnsafeUtil (file:/var/lib/jenkins/workspace/Manual%20PR%20Test%20(local-tests)/third_party/closure/compiler.jar) to field java.nio.Buffer.address
WARNING: Please consider reporting this to the maintainers of com.google.protobuf.UnsafeUtil
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
/var/lib/jenkins/workspace/Manual PR Test (local-tests)/lib/polyfill/indexed_db.js:42: ERROR - Suspicious code. The result of the 'getprop' operator is not being used.
window.indexedDB;
^^^^^^^^^^^^^^^^

1 error(s), 0 warning(s), 90.4% typed
Build failed
END-BUILD: FAILURE
Build step 'Execute shell' marked build as failure

[gikrauss]

I've refactored this code a bit to avoid the previous error ("The result of the 'getprop' operator is not being used"). Additionally, this caused the compiler to completely remove this code.

The compiled version, with this refactor is:
var b=!1;if(Ic("CrKey"))b=!0;else try{window.indexedDB&&(b=!1)}catch(c){b=!0}b&&delete window.indexedDB}

[joeyparrish]

Looks good. Thanks!

[shaka-bot]

Test Failure:

Generating Closure dependencies...
Linting JavaScript...

/var/lib/jenkins/workspace/Manual PR Test (local-tests)/lib/polyfill/indexed_db.js
41:1  error  Line 41 exceeds the maximum line length of 80  max-len
47:1  error  Line 47 exceeds the maximum line length of 80  max-len

✖ 2 problems (2 errors, 0 warnings)

END-BUILD: FAILURE
Build step 'Execute shell' marked build as failure

[gikrauss]

Fixed max line length exceeded

[shaka-bot]

All tests passed!

[joeyparrish]

Thanks so much for the contribution!