[TTS][Template URL] Add support for exact-search.

Adds support for a new Contextual Search Resolve request parameter:
"ctxsl_exact" boolean used to restrict the server to only resolve
a search for the exact selection.  This means the returned Search
Term is restricted to the exact selection and the selection will
not be expanded.  This is needed for user-adjusted selections
as part of the Long-press triggering experiment.

BUG=956277

Change-Id: I5f1285ce04bd4afff7250fbc76bca79c4da0dbf7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1994265
Commit-Queue: Donn Denman <donnd@chromium.org>
Auto-Submit: Donn Denman <donnd@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733058}

chrome/browser/android/contextualsearch/contextual_search_delegate.cc

@@ -285,10 +285,12 @@ std::string ContextualSearchDelegate::BuildRequestUrl(
     contextual_cards_version = field_trial_->GetContextualCardsVersion();
   }
 
+  // TODO(donnd): use a passed-in value for is_search_exact ASAP (CL pending).
+  bool is_exact_search = false;
   TemplateURLRef::SearchTermsArgs::ContextualSearchParams params(
       kContextualSearchRequestVersion, contextual_cards_version,
       context->GetHomeCountry(), context->GetPreviousEventId(),
-      context->GetPreviousEventResults());
+      context->GetPreviousEventResults(), is_exact_search);
 
   search_terms_args.contextual_search_params = params;
 

components/search_engines/template_url.cc

@@ -216,23 +216,21 @@ size_t TemplateURLRef::SearchTermsArgs::EstimateMemoryUsage() const {
 }
 
 TemplateURLRef::SearchTermsArgs::ContextualSearchParams::
-    ContextualSearchParams()
-    : version(-1),
-      contextual_cards_version(0),
-      previous_event_id(0),
-      previous_event_results(0) {}
+    ContextualSearchParams() = default;
 
 TemplateURLRef::SearchTermsArgs::ContextualSearchParams::ContextualSearchParams(
     int version,
     int contextual_cards_version,
     const std::string& home_country,
     int64_t previous_event_id,
-    int previous_event_results)
+    int previous_event_results,
+    bool is_exact_search)
     : version(version),
       contextual_cards_version(contextual_cards_version),
       home_country(home_country),
       previous_event_id(previous_event_id),
-      previous_event_results(previous_event_results) {}
+      previous_event_results(previous_event_results),
+      is_exact_search(is_exact_search) {}
 
 TemplateURLRef::SearchTermsArgs::ContextualSearchParams::ContextualSearchParams(
     const ContextualSearchParams& other) = default;
@@ -995,6 +993,8 @@ std::string TemplateURLRef::HandleReplacements(
           args.push_back("ctxsl_per=" +
                          base::NumberToString(params.previous_event_results));
         }
+        if (params.is_exact_search)
+          args.push_back("ctxsl_exact=1");
 
         HandleReplacement(std::string(), base::JoinString(args, "&"), *i, &url);
         break;

components/search_engines/template_url.h

@@ -107,11 +107,17 @@ class TemplateURLRef {
       // The |previous_event_results| are the results of the user-interaction of
       // that previous request.
       // The "previous_xyz" parameters are documented in go/cs-sanitized.
+      // The |is_exact_search| allows the search request to be narrowed down to
+      // an "exact" search only, meaning just search for X rather than X +
+      // whatever else is in the context.  The returned search term should not
+      // be expanded, and the server will honor this along with creating a
+      // narrow Search Term.
       ContextualSearchParams(int version,
                              int contextual_cards_version,
                              const std::string& home_country,
                              int64_t previous_event_id,
-                             int previous_event_results);
+                             int previous_event_results,
+                             bool is_exact_search);
       ContextualSearchParams(const ContextualSearchParams& other);
       ~ContextualSearchParams();
 
@@ -120,11 +126,11 @@ class TemplateURLRef {
       size_t EstimateMemoryUsage() const;
 
       // The version of contextual search.
-      int version;
+      int version = -1;
 
       // The version of Contextual Cards data to request.
       // A value of 0 indicates no data needed.
-      int contextual_cards_version;
+      int contextual_cards_version = 0;
 
       // The locale of the user's home country in an ISO country code format,
       // or an empty string if not available.  This indicates where the user
@@ -133,11 +139,15 @@ class TemplateURLRef {
 
       // An EventID from a previous interaction (sent by server, recorded by
       // client).
-      int64_t previous_event_id;
+      int64_t previous_event_id = 0l;
 
       // An encoded set of booleans that represent the interaction results from
       // the previous event.
-      int previous_event_results;
+      int previous_event_results = 0;
+
+      // A flag that restricts the search to exactly match the selection rather
+      // than expanding the Search Term to include other words in the context.
+      bool is_exact_search = false;
     };
 
     // Estimates dynamic memory usage.

components/search_engines/template_url_unittest.cc

@@ -1741,7 +1741,7 @@ TEST_F(TemplateURLTest, ContextualSearchParameters) {
   // Test the current common case, which uses no home country or previous
   // event.
   TemplateURLRef::SearchTermsArgs::ContextualSearchParams params(
-      2, 1, std::string(), 0, 0);
+      2, 1, std::string(), 0, 0, false);
   search_terms_args.contextual_search_params = params;
   result = url.url_ref().ReplaceSearchTerms(search_terms_args,
                                             search_terms_data_);
@@ -1753,8 +1753,8 @@ TEST_F(TemplateURLTest, ContextualSearchParameters) {
 
   // Test the home country and non-zero event data case.
   search_terms_args.contextual_search_params =
-      TemplateURLRef::SearchTermsArgs::ContextualSearchParams(2, 2, "CH",
-                                                              1657713458, 5);
+      TemplateURLRef::SearchTermsArgs::ContextualSearchParams(
+          2, 2, "CH", 1657713458, 5, false);
   result =
       url.url_ref().ReplaceSearchTerms(search_terms_args, search_terms_data_);
 
@@ -1766,6 +1766,17 @@ TEST_F(TemplateURLTest, ContextualSearchParameters) {
       "ctxsl_pid=1657713458&"
       "ctxsl_per=5",
       result);
+
+  // Test exact-search.
+  search_terms_args.contextual_search_params =
+      TemplateURLRef::SearchTermsArgs::ContextualSearchParams(
+          2, 1, std::string(), 0, 0, true);
+  result =
+      url.url_ref().ReplaceSearchTerms(search_terms_args, search_terms_data_);
+
+  // Find our param.
+  size_t found_pos = result.find("ctxsl_exact=1");
+  EXPECT_NE(found_pos, std::string::npos);
 }
 
 TEST_F(TemplateURLTest, GenerateKeyword) {