After deliberation, we decided to go with a component name more general than just 'ranker', since parts of the ranker (model loader, model inference) may be of general use for other machine_intelligence applications. I belive 'machine_intelligence' would be a suitable name.

Relevant documentation:
go/chromeranker
go/translateranker

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/97b0ab02964dac76c919c24cac8b50ad1141cd24

commit 97b0ab02964dac76c919c24cac8b50ad1141cd24
Author: hamelphi <hamelphi@chromium.org>
Date: Tue Jun 27 21:41:58 2017

Move ranker_model_loader to a new component.

This change should not incur any behavior change. It moves the RankerModelLoader code from components/translate to a new component. The ModelLoader (and other parts of Ranker) will be re-used by contextual_search (and probably other components eventually).

The plan for the machine_intelligence component is that it will hold the code for machine intelligence features in Chrome. In the short term, we plan to put the Ranker code here (go/chromeranker), including the ModelLoader, example logging and model inference.

The ModelLoader is the first part to be moved out of Translate, since it is already ready for re-use by other components (e.g. Contextual Search). Other parts will need to be refactored first before we move them out of the Translate component.

BUG= 731845 

Review-Url: https://codereview.chromium.org/2925733002
Cr-Commit-Position: refs/heads/master@{#482754}

[modify] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/BUILD.gn
[modify] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/data_use_measurement/core/data_use_user_data.cc
[modify] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/data_use_measurement/core/data_use_user_data.h
[add] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/BUILD.gn
[add] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/DEPS
[add] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/OWNERS
[rename] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/proto/BUILD.gn
[rename] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/proto/ranker_model.proto
[rename] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/proto/translate_ranker_model.proto
[rename] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/ranker_model.cc
[rename] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/ranker_model.h
[rename] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/ranker_model_loader.cc
[rename] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/ranker_model_loader.h
[rename] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/ranker_model_loader_unittest.cc
[rename] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/ranker_model_unittest.cc
[add] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/ranker_url_fetcher.cc
[add] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/machine_intelligence/ranker_url_fetcher.h
[modify] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/translate/core/browser/BUILD.gn
[modify] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/translate/core/browser/DEPS
[modify] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/translate/core/browser/translate_ranker_impl.cc
[modify] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/translate/core/browser/translate_ranker_impl.h
[modify] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/translate/core/browser/translate_ranker_impl_unittest.cc
[modify] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/components/translate/core/browser/translate_url_fetcher.cc
[modify] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/tools/metrics/histograms/enums.xml
[modify] https://crrev.com/97b0ab02964dac76c919c24cac8b50ad1141cd24/tools/metrics/histograms/histograms.xml