Make providers report their type on update, and add hook to controller

This is CL #2 for integration testing. It uses the new ResultType method
to allow search providers to report _which_ provider is returning
results on an update to the SearchController.

The SearchController has also had a callback hook added, which is passed
the updated result type on each call. This hook can be used by a browser
test to control a run loop that stops when the desired set of providers
have returned.

See the CL description in crrev.com/c/2214736 for more details on the
implementation plan for integration tests.

Bug: 1086713
Change-Id: Iedd8e7ce6824dc6c90623837342456db26494069
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2217945Reviewed-by: Thanh Nguyen <thanhdng@chromium.org>
Commit-Queue: Tony Yeoman <tby@chromium.org>
Cr-Commit-Position: refs/heads/master@{#774536}

chrome/browser/ui/app_list/search/search_controller.cc

@@ -5,13 +5,11 @@
 #include "chrome/browser/ui/app_list/search/search_controller.h"
 
 #include <algorithm>
-#include <memory>
-#include <utility>
-#include <vector>
 
 #include "ash/public/cpp/app_list/app_list_config.h"
 #include "ash/public/cpp/app_list/app_list_features.h"
 #include "ash/public/cpp/app_list/app_list_metrics.h"
+#include "ash/public/cpp/app_list/app_list_types.h"
 #include "ash/public/cpp/tablet_mode.h"
 #include "base/bind.h"
 #include "base/metrics/histogram_macros.h"
@@ -144,11 +142,19 @@ size_t SearchController::AddGroup(size_t max_results,
 void SearchController::AddProvider(size_t group_id,
                                    std::unique_ptr<SearchProvider> provider) {
   provider->set_result_changed_callback(
-      base::Bind(&SearchController::OnResultsChanged, base::Unretained(this)));
+      base::Bind(&SearchController::OnResultsChangedWithType,
+                 base::Unretained(this), provider->ResultType()));
   mixer_->AddProviderToGroup(group_id, provider.get());
   providers_.emplace_back(std::move(provider));
 }
 
+void SearchController::OnResultsChangedWithType(
+    ash::AppListSearchResultType result_type) {
+  OnResultsChanged();
+  if (results_changed_callback_)
+    results_changed_callback_.Run(result_type);
+}
+
 void SearchController::OnResultsChanged() {
   if (dispatching_query_)
     return;

chrome/browser/ui/app_list/search/search_controller.h

@@ -9,8 +9,10 @@
 
 #include <memory>
 #include <string>
+#include <utility>
 #include <vector>
 
+#include "base/callback.h"
 #include "base/macros.h"
 #include "base/strings/string16.h"
 #include "chrome/browser/ui/app_list/search/mixer.h"
@@ -23,6 +25,7 @@ class Profile;
 
 namespace ash {
 class AppListNotifier;
+enum class AppListSearchResultType;
 }
 
 namespace app_list {
@@ -36,6 +39,9 @@ enum class RankingItemType;
 // results to the given SearchResults UI model.
 class SearchController {
  public:
+  using ResultsChangedCallback =
+      base::RepeatingCallback<void(ash::AppListSearchResultType)>;
+
   SearchController(AppListModelUpdater* model_updater,
                    AppListControllerDelegate* list_controller,
                    ash::AppListNotifier* notifier,
@@ -78,9 +84,16 @@ class SearchController {
       const ash::SearchResultIdWithPositionIndices& results,
       int launched_index);
 
+  void set_results_changed_callback_for_test(ResultsChangedCallback callback) {
+    results_changed_callback_ = std::move(callback);
+  }
+
  private:
-  // Invoked when the search results are changed.
+  // Invoked when the search results are changed. Providers should use the one
+  // argument version, and pass the primary type of result produced by the
+  // invoking search provider.
   void OnResultsChanged();
+  void OnResultsChangedWithType(ash::AppListSearchResultType result_type);
 
   Profile* profile_;
 
@@ -96,6 +109,9 @@ class SearchController {
   // recording.
   std::string last_launched_app_id_;
 
+  // If set, called when OnResultsChanged is invoked.
+  ResultsChangedCallback results_changed_callback_;
+
   std::unique_ptr<Mixer> mixer_;
   std::unique_ptr<SearchMetricsObserver> metrics_observer_;
   using Providers = std::vector<std::unique_ptr<SearchProvider>>;