[TTS] Write initial Tap-features to Ranker.

This is an initial write-to-Ranker change that just writes features
that we already have on-hand to validate the feature-write mechanism.

This introduces a new native class that does the actual feature writing
to Ranker.  This class is connected to an existing Java feature collection
stub (implemented a few months ago).

All new code is behind a new flag, so nothing should change by default.

Still TODO: Tests.

BUG=676108

Review-Url: https://codereview.chromium.org/2857333002
Cr-Commit-Position: refs/heads/master@{#473234}
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index e4d3ef5..bcc9520d 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -2818,6 +2818,8 @@
       "android/contextualsearch/contextual_search_field_trial.h",
       "android/contextualsearch/contextual_search_manager.cc",
       "android/contextualsearch/contextual_search_manager.h",
+      "android/contextualsearch/contextual_search_ranker_logger_impl.cc",
+      "android/contextualsearch/contextual_search_ranker_logger_impl.h",
       "android/contextualsearch/contextual_search_tab_helper.cc",
       "android/contextualsearch/contextual_search_tab_helper.h",
       "android/contextualsearch/ctr_suppression.cc",
@@ -4149,6 +4151,7 @@
       "../android/java/src/org/chromium/chrome/browser/contextmenu/ContextMenuParams.java",
       "../android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchContext.java",
       "../android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManager.java",
+      "../android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchRankerLoggerImpl.java",
       "../android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchTabHelper.java",
       "../android/java/src/org/chromium/chrome/browser/contextualsearch/CtrSuppression.java",
       "../android/java/src/org/chromium/chrome/browser/cookies/CookiesFetcher.java",