Use DownloadManager::Observer in TestDownloadShelf

Use DownloadManager::Observer in TestDownloadShelf

Use DownloadManager::Observer interface to track the lifetime of
DownloadManager instead of keeping a counted reference to it.

This will easy the transition of DownloadManager from being refcounted
to be owned by the BrowserContext.

BUG=237871
TEST=unit_tests with filter for Download\*

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=201768

[benjhayden, 2013-05-21 18:14:28]

https://codereview.chromium.org/15575002/diff/1/chrome/browser/download/test_...
File chrome/browser/download/test_download_shelf.cc (right):

https://codereview.chromium.org/15575002/diff/1/chrome/browser/download/test_...
chrome/browser/download/test_download_shelf.cc:42: DCHECK(manager ==
download_manager_);
DCHECK_EQ?

https://codereview.chromium.org/15575002/diff/1/chrome/browser/download/test_...
chrome/browser/download/test_download_shelf.cc:65: return NULL;
Why not just return download_manager_?

[cmarcelo, 2013-05-21 18:21:04]

Updated.

[benjhayden, 2013-05-21 18:53:37]

lgtm

[benjhayden, 2013-05-21 19:40:04]

../../chrome/browser/download/test_download_shelf.h:33:67:error:
[chromium-style] Overriding method must be marked with OVERRIDE.
  virtual void ManagerGoingDown(content::DownloadManager* manager);

[cmarcelo, 2013-05-21 19:41:28]

On 2013/05/21 19:40:04, benjhayden_chromium wrote:
> ../../chrome/browser/download/test_download_shelf.h:33:67:error:
> [chromium-style] Overriding method must be marked with OVERRIDE.
>   virtual void ManagerGoingDown(content::DownloadManager* manager);

I saw that, thanks. I fixed this and rebased the patch to upload it again.
(taking time to compile and test)

[benjhayden, 2013-05-21 20:10:43]

Ok, just re-mail when you've uploaded the fix and we'll put it back on the try
bots until they're green.

[cmarcelo, 2013-05-21 20:31:31]

Updated to add missing OVERRIDE.

[cmarcelo, 2013-05-22 17:29:57]

Those errors doesn't seem related to the patch. Should we trigger the CQ to make
it try again?

[commit-bot: I haz the power, 2013-05-22 17:38:01]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/caio.de.oliveira.filho@intel.com/15575...

[commit-bot: I haz the power, 2013-05-23 05:19:13]

Retried try job too often on win_rel for step(s) browser_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[commit-bot: I haz the power, 2013-05-23 11:40:52]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/caio.de.oliveira.filho@intel.com/15575...

[commit-bot: I haz the power, 2013-05-23 12:47:09]

Change committed as 201768