[TTS] Add home country to TemplateURLRef ContextualSearch.

Adds another parameter to the ContextualSearchParams that is used to
specify the home country of the user.  This indicates where the user
resides, not where they currently are.

Removes old legacy constructors and updates iOS usage for the sole new constructor.

BUG=679853

Review-Url: https://codereview.chromium.org/2623993003
Cr-Commit-Position: refs/heads/master@{#444160}
diff --git a/components/search_engines/template_url_unittest.cc b/components/search_engines/template_url_unittest.cc
index 9fd790c..f6309f5 100644
--- a/components/search_engines/template_url_unittest.cc
+++ b/components/search_engines/template_url_unittest.cc
@@ -1691,34 +1691,29 @@
                                                         search_terms_data_);
   EXPECT_EQ("http://bar/_/contextualsearch?", result);
 
-  TemplateURLRef::SearchTermsArgs::ContextualSearchParams params(
-      1, 6, 11, "allen", "woody+allen+movies", "www.wikipedia.org", "utf-8", 1);
+  // Test the current common case, which uses no home country.
+  TemplateURLRef::SearchTermsArgs::ContextualSearchParams params(2, 1,
+                                                                 std::string());
   search_terms_args.contextual_search_params = params;
   result = url.url_ref().ReplaceSearchTerms(search_terms_args,
                                             search_terms_data_);
   EXPECT_EQ(
       "http://bar/_/contextualsearch?"
-      "ctxs=1&"
-      "ctxs_start=6&"
-      "ctxs_end=11&"
-      "q=allen&"
-      "ctxs_content=woody+allen+movies&"
-      "ctxsl_url=www.wikipedia.org&"
-      "ctxs_encoding=utf-8&"
+      "ctxs=2&"
       "ctxsl_coca=1",
       result);
 
-  // Test the current common case, which uses the shorter constructor.
+  // Test the home country case.
   search_terms_args.contextual_search_params =
-      TemplateURLRef::SearchTermsArgs::ContextualSearchParams(2, "allen",
-                                                              std::string(), 0);
+      TemplateURLRef::SearchTermsArgs::ContextualSearchParams(2, 2, "CH");
   result =
       url.url_ref().ReplaceSearchTerms(search_terms_args, search_terms_data_);
 
   EXPECT_EQ(
       "http://bar/_/contextualsearch?"
       "ctxs=2&"
-      "q=allen",
+      "ctxsl_coca=2&"
+      "ctxs_hc=CH",
       result);
 }