ambient: Pass the topic batch size to server

Bug: b/157099464
Test: pass current tests.
Change-Id: Ie364f743da23dc73b136c77416a630db3ba6e840
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2209891Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Commit-Queue: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771145}

ash/ambient/ambient_photo_controller.cc

@@ -22,6 +22,8 @@ namespace ash {
 
 namespace {
 
+constexpr int kNumberTopics = 100;
+
 using DownloadCallback = base::OnceCallback<void(const gfx::ImageSkia&)>;
 
 void DownloadImageFromUrl(const std::string& url, DownloadCallback callback) {
@@ -44,6 +46,7 @@ void AmbientPhotoController::StartScreenUpdate() {
       ->ambient_controller()
       ->ambient_backend_controller()
       ->FetchScreenUpdateInfo(
+          kNumberTopics,
           base::BindOnce(&AmbientPhotoController::OnScreenUpdateInfoFetched,
                          weak_factory_.GetWeakPtr()));
 }

ash/ambient/backdrop/ambient_backend_controller_impl.cc

@@ -176,12 +176,13 @@ AmbientBackendControllerImpl::AmbientBackendControllerImpl() = default;
 AmbientBackendControllerImpl::~AmbientBackendControllerImpl() = default;
 
 void AmbientBackendControllerImpl::FetchScreenUpdateInfo(
+    int num_topics,
     OnScreenUpdateInfoFetchedCallback callback) {
   // Consolidate the functions of FetchScreenUpdateInfoInternal,
   // StartToGetSettings, and StartToUpdateSettings after this is done.
   Shell::Get()->ambient_controller()->RequestAccessToken(base::BindOnce(
       &AmbientBackendControllerImpl::FetchScreenUpdateInfoInternal,
-      weak_factory_.GetWeakPtr(), std::move(callback)));
+      weak_factory_.GetWeakPtr(), num_topics, std::move(callback)));
 }
 
 void AmbientBackendControllerImpl::GetSettings(GetSettingsCallback callback) {
@@ -207,6 +208,7 @@ void AmbientBackendControllerImpl::SetPhotoRefreshInterval(
 }
 
 void AmbientBackendControllerImpl::FetchScreenUpdateInfoInternal(
+    int num_topics,
     OnScreenUpdateInfoFetchedCallback callback,
     const std::string& gaia_id,
     const std::string& access_token) {
@@ -220,7 +222,7 @@ void AmbientBackendControllerImpl::FetchScreenUpdateInfoInternal(
   std::string client_id = GetClientId();
   BackdropClientConfig::Request request =
       backdrop_client_config_.CreateFetchScreenUpdateRequest(
-          gaia_id, access_token, client_id);
+          num_topics, gaia_id, access_token, client_id);
   auto resource_request = CreateResourceRequest(request);
 
   auto backdrop_url_loader = std::make_unique<BackdropURLLoader>();

ash/ambient/backdrop/ambient_backend_controller_impl.h

@@ -26,6 +26,7 @@ class AmbientBackendControllerImpl : public AmbientBackendController {
 
   // AmbientBackendController:
   void FetchScreenUpdateInfo(
+      int num_topics,
       OnScreenUpdateInfoFetchedCallback callback) override;
   void GetSettings(GetSettingsCallback callback) override;
   void UpdateSettings(AmbientModeTopicSource topic_source,
@@ -36,7 +37,8 @@ class AmbientBackendControllerImpl : public AmbientBackendController {
   using BackdropClientConfig = chromeos::ambient::BackdropClientConfig;
   void RequestAccessToken(AmbientClient::GetAccessTokenCallback callback);
 
-  void FetchScreenUpdateInfoInternal(OnScreenUpdateInfoFetchedCallback callback,
+  void FetchScreenUpdateInfoInternal(int num_topics,
+                                     OnScreenUpdateInfoFetchedCallback callback,
                                      const std::string& gaia_id,
                                      const std::string& access_token);
 

ash/ambient/fake_ambient_backend_controller_impl.cc

@@ -25,6 +25,7 @@ FakeAmbientBackendControllerImpl::FakeAmbientBackendControllerImpl() = default;
 FakeAmbientBackendControllerImpl::~FakeAmbientBackendControllerImpl() = default;
 
 void FakeAmbientBackendControllerImpl::FetchScreenUpdateInfo(
+    int num_topics,
     OnScreenUpdateInfoFetchedCallback callback) {
   ash::AmbientModeTopic topic;
   topic.url = kFakeUrl;

ash/ambient/fake_ambient_backend_controller_impl.h

@@ -20,6 +20,7 @@ class ASH_EXPORT FakeAmbientBackendControllerImpl
 
   // AmbientBackendController:
   void FetchScreenUpdateInfo(
+      int num_topics,
       OnScreenUpdateInfoFetchedCallback callback) override;
   void GetSettings(GetSettingsCallback callback) override;
   void UpdateSettings(AmbientModeTopicSource topic_source,

ash/public/cpp/ambient/ambient_backend_controller.h

@@ -97,11 +97,13 @@ class ASH_PUBLIC_EXPORT AmbientBackendController {
   AmbientBackendController& operator=(const AmbientBackendController&) = delete;
   virtual ~AmbientBackendController();
 
-  // Sends request to retrieve |ScreenUpdate| from the backdrop server.
+  // Sends request to retrieve |num_topics| of |ScreenUpdate| from the backdrop
+  // server.
   // Upon completion, |callback| is run with the parsed |ScreenUpdate|. If any
   // errors happened during the process, e.g. failed to fetch access token, a
   // dummy instance will be returned.
   virtual void FetchScreenUpdateInfo(
+      int num_topics,
       OnScreenUpdateInfoFetchedCallback callback) = 0;
 
   // Get ambient mode Settings from server.