Add skeletons for the factories to create the request coordinator and

components/offline_pages/background/request_coordinator.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_COORDINATOR_H_
 #define COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_COORDINATOR_H_
 
 #include "base/callback.h"
+#include "components/keyed_service/core/keyed_service.h"
 
 namespace offline_pages {
 
+class OfflinerPolicy;
+class OfflinerFactory;
+class Offliner;
+
 // Coordinates queueing and processing save page later requests.
-class RequestCoordinator {
+class RequestCoordinator : public KeyedService {
  public:
   // Callback to report when the processing of a triggered task is complete.
   typedef base::Callback<void()> ProcessingDoneCallback;
 
   struct SavePageRequest {

[fgorski, 2016/05/03 22:48:17]

remove this.

[Pete Williamson, 2016/05/04 00:39:22]

Done.

     // TODO(dougarnett): define and consider making stand-alone.
   };
 
-  // TODO(dougarnett): How to inject Offliner factories and policy objects.
-  RequestCoordinator();
-
-  ~RequestCoordinator();
+  ~RequestCoordinator() override;
 
   // Queues |request| to later load and save when system conditions allow.
   bool SavePageLater(const SavePageRequest& request);
 
   // Starts processing of one or more queued save page later requests.
   // Returns whether processing was started and that caller should expect
   // a callback. If processing was already active, returns false.
   bool StartProcessing(const ProcessingDoneCallback& callback);
 
   // Stops the current request processing if active. This is a way for
   // caller to abort processing; otherwise, processing will complete on
   // its own. In either case, the callback will be called when processing
   // is stopped or complete.
   void StopProcessing();
 
-  // TODO(dougarnett): add policy support methods.
+  // Factory has permission to call our private constructor.
+  friend class RequestCoordinatorFactory;

[fgorski, 2016/05/03 22:48:16]

I don't think you need this.
Constructor can be public even when you are using the factory.

After all you may want to test this thing.

[Pete Williamson, 2016/05/04 00:39:22]

Removed.  I'm happy without it, but I thought I recalled that normal practice
was to hide the Ctor of anything with a factory.

+
+ private:
+  RequestCoordinator(
+      OfflinerPolicy* policy, OfflinerFactory* factory);
+
+  OfflinerPolicy* policy_;

[fgorski, 2016/05/03 22:48:16]

this should be a unique_ptr.

[Pete Williamson, 2016/05/04 00:39:21]

Can I use a unique ptr if I am going to pass a pointer to the same object to the
request queue and offliner?  I'm not sure which is the best pointer, maybe
shared_ptr?

[fgorski, 2016/05/04 05:20:57]

Here is how I see this:
1. RC owns the policy (unique_ptr is apropriate)
2. RC owns the request_queue (another unique_ptr)
3. RC passes the raw ptr to the request_queue and inside of it you make a
comment about 1 and 2

Don't think of unique_ptr as: there is only one pointer to the object, but
rather: there is only one handle that manages life of that object.

Here is a relevant discussion of the problem I found:
https://herbsutter.com/2013/06/05/gotw-91-solution-smart-pointer-parameters/

[Pete Williamson, 2016/05/04 21:23:21]

Done.

+  OfflinerFactory* factory_;

[fgorski, 2016/05/03 22:48:17]

who controls the life of a factory?

[Pete Williamson, 2016/05/04 00:39:22]

The request coordinator should control the lifetime of any offliner factory it
makes.

[fgorski, 2016/05/04 05:20:57]

unique_ptr then? per response above.

[Pete Williamson, 2016/05/04 21:23:21]

Done.

+  int factoryArraySize_;

[fgorski, 2016/05/03 22:48:17]

?

[Pete Williamson, 2016/05/04 00:39:22]

Oops, leftover.  Removed.

 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_COORDINATOR_H_