Fetch snippets from ChromeReader and show them on the NTP

components/ntp_snippets/ntp_snippets_service.cc

Index: components/ntp_snippets/ntp_snippets_service.cc
diff --git a/components/ntp_snippets/ntp_snippets_service.cc b/components/ntp_snippets/ntp_snippets_service.cc
index f3c0670f7af808486dbfd6cd80572c73bfc971f5..2e7db027da71a99b4546928cfeb0cfbbe2df1f36 100644
--- a/components/ntp_snippets/ntp_snippets_service.cc
+++ b/components/ntp_snippets/ntp_snippets_service.cc
@@ -4,14 +4,36 @@
 
 #include "components/ntp_snippets/ntp_snippets_service.h"
 
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
 #include "base/json/json_string_value_serializer.h"
+#include "base/location.h"
+#include "base/path_service.h"
+#include "base/task_runner_util.h"
 #include "base/values.h"
 
 namespace ntp_snippets {
 
+std::string ReadFileToString(const base::FilePath& path) {
+  std::string data;
+  bool success = base::ReadFileToString(path, &data);
+  DLOG_IF(ERROR, !success) << "Error reading file " << path.LossyDisplayName();
+  return data;
+}
+
 NTPSnippetsService::NTPSnippetsService(
-    const std::string& application_language_code)
-    : loaded_(false), application_language_code_(application_language_code) {}
+    scoped_refptr<base::SequencedTaskRunner> file_task_runner,
+    const std::string& application_language_code,
+    NTPSnippetsFetcher* snippets_fetcher)
+    : loaded_(false),
+      file_task_runner_(file_task_runner),
+      application_language_code_(application_language_code),
+      snippets_fetcher_(snippets_fetcher),
+      weak_ptr_factory_(this) {
+  snippets_fetcher_callback_ = snippets_fetcher_->AddCallback(
+      base::Bind(&NTPSnippetsService::OnSnippetsDownloaded,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
 
 NTPSnippetsService::~NTPSnippetsService() {}
 
@@ -21,6 +43,10 @@ void NTPSnippetsService::Shutdown() {
   loaded_ = false;
 }
 
+void NTPSnippetsService::FetchSnippets(bool overwrite) {
+  snippets_fetcher_->FetchSnippets(overwrite);
+}
+
 void NTPSnippetsService::AddObserver(NTPSnippetsServiceObserver* observer) {
   observers_.AddObserver(observer);
   if (loaded_)
@@ -31,6 +57,10 @@ void NTPSnippetsService::RemoveObserver(NTPSnippetsServiceObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
+void NTPSnippetsService::OnFileReadDone(const std::string& json) {
+  LoadFromJSONString(json);
+}
+
 bool NTPSnippetsService::LoadFromJSONString(const std::string& str) {
   JSONStringValueDeserializer deserializer(str);
   int error_code;
@@ -64,9 +94,19 @@ bool NTPSnippetsService::LoadFromJSONString(const std::string& str) {
     snippets_.push_back(std::move(snippet));
   }
   loaded_ = true;
+
   FOR_EACH_OBSERVER(NTPSnippetsServiceObserver, observers_,
                     NTPSnippetsServiceLoaded(this));
   return true;
 }
 
+void NTPSnippetsService::OnSnippetsDownloaded(
+    const base::FilePath download_path) {
+  base::PostTaskAndReplyWithResult(
+      file_task_runner_.get(), FROM_HERE,
+      base::Bind(&ReadFileToString, download_path),
+      base::Bind(&NTPSnippetsService::OnFileReadDone,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
 }  // namespace ntp_snippets