Refactor the UpdateEngine and its actions in the component updater.

components/update_client/update_engine.h

Index: components/update_client/update_engine.h
diff --git a/components/update_client/update_engine.h b/components/update_client/update_engine.h
index e24b2a178cbda12b92e8547bb9af10c2d213a3ff..cec91f987dcf5e200d36f75e730e6240bebb57e5 100644
--- a/components/update_client/update_engine.h
+++ b/components/update_client/update_engine.h
@@ -5,6 +5,7 @@
 #ifndef COMPONENTS_UPDATE_CLIENT_UPDATE_ENGINE_H_
 #define COMPONENTS_UPDATE_CLIENT_UPDATE_ENGINE_H_
 
+#include <iterator>
 #include <list>
 #include <map>
 #include <memory>
@@ -17,7 +18,8 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/threading/thread_checker.h"
-#include "components/update_client/action.h"
+#include "base/time/time.h"
+#include "components/update_client/component.h"
 #include "components/update_client/component_patcher_operation.h"
 #include "components/update_client/crx_downloader.h"
 #include "components/update_client/crx_update_item.h"
@@ -28,7 +30,6 @@
 namespace base {
 class TimeTicks;
 class SequencedTaskRunner;
-class SingleThreadTaskRunner;
 }  // namespace base
 
 namespace update_client {
@@ -61,13 +62,37 @@ class UpdateEngine {
               const UpdateClient::CrxDataCallback& crx_data_callback,
               const Callback& update_callback);
 
+  void SendUninstallPing(const std::string& id,
+                         const base::Version& version,
+                         int reason,
+                         const Callback& update_callback);
+
  private:
-  void UpdateComplete(UpdateContext* update_context, Error error);
+  using UpdateContexts = std::set<std::unique_ptr<UpdateContext>>;
+  using UpdateContextIterator = UpdateContexts::iterator;
+
+  void UpdateComplete(const UpdateContextIterator& it, Error error);
+
+  void ComponentCheckingForUpdatesStart(const UpdateContextIterator& it,
+                                        const Component& component);
+  void ComponentCheckingForUpdatesComplete(const UpdateContextIterator& it,
+                                           const Component& component);
+  void UpdateCheckComplete(const UpdateContextIterator& it);
+
+  void DoUpdateCheck(const UpdateContextIterator& it);
+  void UpdateCheckDone(const UpdateContextIterator& it,
+                       int error,
+                       int retry_after_sec);
+
+  void HandleComponent(const UpdateContextIterator& it);
+  void HandleComponentComplete(const UpdateContextIterator& it);
 
   // Returns true if the update engine rejects this update call because it
   // occurs too soon.
   bool IsThrottled(bool is_foreground) const;
 
+  // base::TimeDelta GetNextUpdateDelay(const Component& component) const;
+
   base::ThreadChecker thread_checker_;
 
   scoped_refptr<Configurator> config_;
@@ -84,7 +109,7 @@ class UpdateEngine {
   const NotifyObserversCallback notify_observers_callback_;
 
   // Contains the contexts associated with each update in progress.
-  std::set<UpdateContext*> update_contexts_;
+  UpdateContexts update_contexts_;
 
   // Implements a rate limiting mechanism for background update checks. Has the
   // effect of rejecting the update call if the update call occurs before
@@ -104,16 +129,14 @@ struct UpdateContext {
       const UpdateClient::CrxDataCallback& crx_data_callback,
       const UpdateEngine::NotifyObserversCallback& notify_observers_callback,
       const UpdateEngine::Callback& callback,
-      UpdateChecker::Factory update_checker_factory,
-      CrxDownloader::Factory crx_downloader_factory,
-      PingManager* ping_manager);
+      CrxDownloader::Factory crx_downloader_factory);
 
   ~UpdateContext();
 
   scoped_refptr<Configurator> config;
 
   // True if this update has been initiated by the user.
-  bool is_foreground;
+  bool is_foreground = false;
 
   // True if the component updates are enabled in this context.
   const bool enabled_component_updates;
@@ -130,30 +153,34 @@ struct UpdateContext {
   // Called when the all updates associated with this context have completed.
   const UpdateEngine::Callback callback;
 
-  // Posts replies back to the main thread.
-  scoped_refptr<base::SingleThreadTaskRunner> main_task_runner;
-
   // Runs tasks in a blocking thread pool.
   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner;
 
-  // Creates instances of UpdateChecker;
-  UpdateChecker::Factory update_checker_factory;
-
   // Creates instances of CrxDownloader;
   CrxDownloader::Factory crx_downloader_factory;
 
-  PingManager* ping_manager;  // Not owned by this class.
+  std::unique_ptr<UpdateChecker> update_checker;
 
-  std::unique_ptr<Action> current_action;
+  // The time in seconds to wait until doing further update checks.
+  int retry_after_sec = 0;
 
-  // Contains the CrxUpdateItem instances of the items to update.
-  IdToCrxUpdateItemMap update_items;
+  int update_check_error = 0;
+  size_t num_components_ready_to_check = 0;
+  size_t num_components_checked = 0;
 
-  // Contains the ids of the items to update.
-  std::queue<std::string> queue;
+  IdToComponentPtrMap components;
 
-  // The time in seconds to wait until doing further update checks.
-  int retry_after_sec;
+  std::queue<std::string> component_queue;
+
+  // The time to wait before handling the update for a component.
+  // The wait time is proportional with the cost incurred by updating
+  // the component. The more time it takes to download and apply the
+  // update for the current component, the longer the wait until the engine
+  // is handling the next component in the queue.
+  base::TimeDelta next_update_delay;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(UpdateContext);
 };
 
 }  // namespace update_client