Remove params_extractor

[blowmage]

[closes #173]

[codecov[bot]]

Codecov Report

Merging #175 into master will decrease coverage by <.01%. The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #175      +/-   ##
=========================================
- Coverage   98.61%   98.6%   -0.01%     
=========================================
  Files          25      25              
  Lines        1441    1432       -9     
=========================================
- Hits         1421    1412       -9     
  Misses         20      20

Impacted Files	Coverage Δ
lib/google/gax/api_call.rb	97.14% <100%> (-0.59%)	:arrow_down:

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[jbolinger]

Let's update https://github.com/googleapis/gapic-generator-ruby/issues/104 and/or open a PR in the generator to accompany this one so we can see how the usage of this will look from the client side.

[blowmage]

I have updated googleapis/gapic-generator-ruby#94 to be more up to date with the changes made in the GAPIC generator and in Gax. It removes params_extractor from Gax entirely, and demonstrates how the GAPIC generator client can provide that type of functionality.

[jbolinger]

@blowmage I did a quick pass on https://github.com/googleapis/gapic-generator-ruby/pull/94, but it looks like this functionality is still a WIP?

[blowmage]

googleapis/gapic-generator-ruby#94 is a working branch that demonstrates that features can be moved from Gax to the generator. Much of what that branch is using is available to review in #178. Not all of it, but most of it.

[blowmage]

This is satisfied by #178.