feat(ads): allow adsResponse for making ad request

[DDeis]

Currently, shaka throw an error if adTagUrl is not set in imaRequest.
This add the possibility to use a VAST document directly using adsResponse property instead of making a request with an ad tag url.

Resolves #2892

[DDeis]

I'm not sure if that's necessary, I wanted to add unit in ad_manager_unit.js to test shaka.ads.ClientSideAdManager.requestAds but I got stuck in the process.

I added properties to IMA mock, but I don't know how to mock shaka.ads.ClientSideAdManager.eventManager_.
This may be the wrong way of doing it, maybe should I create a separate unit test file for shaka.ads.ClientSideAdManager ?

[TheModMaker]

I don't think this needs a test. It might be nice to have an integration test to verify IMA allows the adTagUrl to be not set, but we don't have any other integration tests.

[DDeis]

I don't think this needs a test. It might be nice to have an integration test to verify IMA allows the adTagUrl to be not set, but we don't have any other integration tests.

I can try to make an integration for that but this is not my forte, I will need some help for that.
For instance, how to load IMA script ?

[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 (62 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.
/var/lib/jenkins/workspace/Manual PR Test (local-tests)/externs/ima.js:35:14: ERROR - [JSC_UNRECOGNIZED_TYPE_ERROR] Bad type annotation. Unknown type google.ima.AdsRequest
35|   /** @param {google.ima.AdsRequest} request */
^

/var/lib/jenkins/workspace/Manual PR Test (local-tests)/externs/ima.js:230:24: ERROR - [JSC_TYPE_PARSE_ERROR] Bad type annotation. expected closing } See https://github.com/google/closure-compiler/wiki/Annotating-JavaScript-for-the-Closure-Compiler for more information.
230|  *   adsResponse: string|undefined,
^

/var/lib/jenkins/workspace/Manual PR Test (local-tests)/externs/shaka/ads.js:58:14: ERROR - [JSC_UNRECOGNIZED_TYPE_ERROR] Bad type annotation. Unknown type google.ima.AdsRequest
58|    * @param {!google.ima.AdsRequest} imaRequest
^

/var/lib/jenkins/workspace/Manual PR Test (local-tests)/lib/ads/client_side_ad_manager.js:84:14: ERROR - [JSC_UNRECOGNIZED_TYPE_ERROR] Bad type annotation. Unknown type google.ima.AdsRequest
84|    * @param {!google.ima.AdsRequest} imaRequest
^

/var/lib/jenkins/workspace/Manual PR Test (local-tests)/lib/ads/client_side_ad_manager.js:88:42: ERROR - [JSC_STRICT_INEXISTENT_PROPERTY] Property adsResponse never defined on imaRequest
88|         imaRequest.adTagUrl || imaRequest.adsResponse,
^^^^^^^^^^^

5 error(s), 0 warning(s), 94.5% typed
Build failed
END-BUILD: FAILURE
Build step 'Execute shell' marked build as failure

[shaka-bot]

All tests passed!