Remove DownloadFileManager in favor of direct ownership of DownloadFiles.

Remove DownloadFileManager in favor of direct ownership of DownloadFiles.

This CL is equivalent to CLs http://codereview.chromium.org/10799005, 
http://codereview.chromium.org/10836293, and
https://chromiumcodereview.appspot.com/10823406, which were previous attempts 
to land the same functionality.  

TBR=jam@chromium.org

BUG=123998
BUG=144751
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=153563

[Randy Smith (Not in Mondays), 2012-08-25 15:20:30]

TBRing John as before.  Ben, WDYT?  PS1 is the last landed CL, PS1-PS2 the
changes I made to deal with the flakiness.  Before landing I'm going to do try
bots (obviously) and a --gtest_repeat=100 for SavePageBrowserTest.* on my linux
box.

[benjhayden, 2012-08-26 16:17:03]

LGTM, one suggestion

https://chromiumcodereview.appspot.com/10867065/diff/2001/chrome/browser/down...
File chrome/browser/download/save_page_browsertest.cc (right):

https://chromiumcodereview.appspot.com/10867065/diff/2001/chrome/browser/down...
chrome/browser/download/save_page_browsertest.cc:231: void
WaitForPersistedDownloadItem() const {
Why not inline this in CheckDownloadHistory()?

[Randy Smith (Not in Mondays), 2012-08-27 15:02:50]

As mentioned verbally, also added bounce off the DB thread in order to flush
updates to that thread.  PTAL?

http://codereview.chromium.org/10867065/diff/2001/chrome/browser/download/sav...
File chrome/browser/download/save_page_browsertest.cc (right):

http://codereview.chromium.org/10867065/diff/2001/chrome/browser/download/sav...
chrome/browser/download/save_page_browsertest.cc:231: void
WaitForPersistedDownloadItem() const {
On 2012/08/26 16:17:03, benjhayden_chromium wrote:
> Why not inline this in CheckDownloadHistory()?

Quite right.  Done.

[benjhayden, 2012-08-27 15:11:10]

Do you want to run all the downloads and save page tests locally 100 times in
addition to the trybots?

LGTM

[Randy Smith (Not in Mondays), 2012-08-27 15:35:42]

On 2012/08/27 15:11:10, benjhayden_chromium wrote:
> Do you want to run all the downloads and save page tests locally 100 times in
> addition to the trybots?
> 
> LGTM

I was planning to do that for SavePage, but wasn't going to bother for
downloads.

[commit-bot: I haz the power, 2012-08-27 17:54:56]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rdsmith@chromium.org/10867065/7001

[Randy Smith (Not in Mondays), 2012-08-27 17:55:33]

<groundhog day>rdsmith@ is submitting a CL to remove
DownloadFileManager</groundhog day>.

[commit-bot: I haz the power, 2012-08-27 22:27:25]

Change committed as 153563