sync: Merge GU retry logic into normal GU

sync: Merge GU retry logic into normal GU

Moves the implementation of the GU retry get updates into the normal GU
cycle.  This should have no impact on behvaior.  The point of this
refactoring is to eliminate an instance of the GetUpdateDelegate.  I
hope to build on that interface in the future, and removing one of its
four implementations should make that work 25% easier.

This CL should retain all the same quirks as the old retry
implemenation.  The timer management is the same.  It also sends up a
special RETRY value for GetUpdatesOrigin when the only reason for
performing an update is a scheduled retry, which was the behavior of the
old code.

This CL also refactors the NudgeTracker's mangement of the
updates_source_.  The old, stateful, implementation was getting out of
hand.  The new implementation should be easier to maintain, especially
as we start to support 'partially successful' sync cycles.

BUG=339984
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=254653

[rlarocque, 2014-02-20 01:46:32]

I know we've discussed this before.  I'm looking to reopen that discussion.

The GetUpdatesDelegate classes are getting bigger.  I expect that soon it will
be necessary to split them up into their own files.  I'd prefer to have only
three of them rather than four, if at all possible.  

Let me know if you want to talk about it.  Otherwise, please review.

[rlarocque, 2014-02-21 20:10:58]

I had intended to send this review to Haitao.  Looks like I sent it to myself
instead.  

Haitao: PTAL.

[rlarocque, 2014-02-25 18:55:24]

ping.

[rlarocque, 2014-02-26 20:46:58]

ping x 2.

[haitaol1, 2014-02-26 22:18:44]

lgtm

[rlarocque, 2014-02-26 22:33:45]

The CQ bit was checked by rlarocque@chromium.org

[commit-bot: I haz the power, 2014-02-26 22:37:38]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rlarocque@chromium.org/171813013/1

[commit-bot: I haz the power, 2014-02-27 00:46:14]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-02-27 00:46:15]

Retried try job too often on linux_chromeos for step(s) sync_unit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_chro...

[rlarocque, 2014-02-28 22:00:19]

The CQ bit was checked by rlarocque@chromium.org

[commit-bot: I haz the power, 2014-02-28 22:02:03]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rlarocque@chromium.org/171813013/130001

[commit-bot: I haz the power, 2014-02-28 22:02:08]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-02-28 22:02:09]

Failed to apply patch for sync/engine/download_unittest.cc:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  can't find file to patch at input line 6
  Perhaps you used the wrong -p or --strip option?
  The text leading up to this was:
  --------------------------
  |Index: sync/engine/download_unittest.cc
  |diff --git a/sync/engine/download_unittest.cc
b/sync/engine/download_unittest.cc
  |index
e114022ea47b994dbcc0c8e2c47f792c8f5259ba..bb4fd3a74e7b30daed79c968e308077d78bf9346
100644
  |--- a/sync/engine/download_unittest.cc
  |+++ b/sync/engine/download_unittest.cc
  --------------------------
  No file to patch.  Skipping patch.
  1 out of 1 hunk ignored

Patch:       sync/engine/download_unittest.cc
Index: sync/engine/download_unittest.cc
diff --git a/sync/engine/download_unittest.cc b/sync/engine/download_unittest.cc
index
e114022ea47b994dbcc0c8e2c47f792c8f5259ba..bb4fd3a74e7b30daed79c968e308077d78bf9346
100644
--- a/sync/engine/download_unittest.cc
+++ b/sync/engine/download_unittest.cc
@@ -211,9 +211,9 @@ TEST_F(DownloadUpdatesTest, RetryTest) {
   nudge_tracker.SetSyncCycleStartTime(t1 + base::TimeDelta::FromSeconds(1));
 
   sync_pb::GetUpdatesMessage gu_msg;
-  RetryGetUpdatesDelegate retry_delegate;
+  NormalGetUpdatesDelegate normal_delegate(nudge_tracker);
   scoped_ptr<GetUpdatesProcessor> processor(
-      BuildGetUpdatesProcessor(retry_delegate));
+      BuildGetUpdatesProcessor(normal_delegate));
   processor->PrepareGetUpdates(request_types(), &gu_msg);
 
   EXPECT_EQ(sync_pb::SyncEnums::RETRY, gu_msg.get_updates_origin());

[rlarocque, 2014-03-03 20:52:33]

The CQ bit was checked by rlarocque@chromium.org

[commit-bot: I haz the power, 2014-03-03 20:53:53]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rlarocque@chromium.org/171813013/150001

[commit-bot: I haz the power, 2014-03-04 04:20:00]

Change committed as 254653