[TTS] Add server-debug, exact-search mixin codes.

Converts the server-debug setting used for CoCa integration debugging
from a single value to a mixin so we can include that at any level
of integration.

Also adds support for the exact-search bit as a CoCa integration
mixin due to lack of support for the additional parameter needed
to support this critical feature correctly.

The need for this is covered in issue 1060669.

BUG=1060669, 1059004, 956277, 985518

Change-Id: I53d5a9acf114e1b84f8821ddf05283eabcd1c30f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2098489
Auto-Submit: Donn Denman <donnd@chromium.org>
Commit-Queue: Theresa  <twellington@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#749355}

chrome/browser/android/contextualsearch/contextual_search_delegate.cc

@@ -285,11 +285,18 @@ std::string ContextualSearchDelegate::BuildRequestUrl(
     contextual_cards_version =
         contextual_search::kContextualCardsTranslationsIntegration;
   }
-  // TODO(donnd): figure out if this is really needed or if the communication
-  // can be done automatically through a FieldTrial config setting.
+  // Mixin the debug setting.
   if (base::FeatureList::IsEnabled(chrome::android::kContextualSearchDebug)) {
-    contextual_cards_version =
-        contextual_search::kContextualCardsDebugIntegration;
+    contextual_cards_version +=
+        contextual_search::kContextualCardsServerDebugMixin;
+  }
+  // Mixin the exact-search setting.
+  // TODO(donnd): remove or merge-away this ugly implementation if we get
+  // approval for the additional parameter used below (in
+  // ContextualSearchParams). It would be better to only have to support
+  // one of these communication methods server-side.
+  if (context->GetExactResolve()) {
+    contextual_cards_version += contextual_search::kExactSearchMixin;
   }
   // Let the field-trial override.
   if (field_trial_->GetContextualCardsVersion() != 0) {

components/contextual_search/core/browser/public.cc

@@ -23,7 +23,11 @@ const int kContextualCardsDefinitionsIntegration = 4;
 const int kContextualCardsTranslationsIntegration = 5;
 
 // For development.
-const int kContextualCardsDebugIntegration = 98;
 const int kContextualCardsDiagnosticIntegration = 99;
 
+// Mixin values. These are a bit mask * 100:
+const int kSimplifiedServerDeprecatedMixin = 100;
+const int kContextualCardsServerDebugMixin = 200;
+const int kExactSearchMixin = 400;
+
 }  // namespace contextual_search

components/contextual_search/core/browser/public.h

@@ -30,12 +30,20 @@ extern const int kContextualCardsTranslationsIntegration;
 
 // Development-level CoCa integration codes.
 
-// For both client and server-side debugging.
-extern const int kContextualCardsDebugIntegration;
 // Generates diagnostics on the client and uses the ENTRYPOINT_UNSPECIFIED for
 // CoCa to return unlimited cards with diagnostics enabled.
 extern const int kContextualCardsDiagnosticIntegration;
 
+// Mixin values. You must choose only one of the above, but any combination
+// of these mixin values.
+
+// Deprecated value that might be sent by an old client.
+extern const int kSimplifiedServerDeprecatedMixin;
+// Activates server-side debugging.
+extern const int kContextualCardsServerDebugMixin;
+// Indicates that the current request is for an exact search.
+extern const int kExactSearchMixin;
+
 // Longpress resolve variations:
 extern const char kLongpressResolveParamName[];
 extern const char kLongpressResolvePreserveTap[];