Fix browser crash on startup.

Fix browser crash on startup.

>	chrome.dll!`anonymous namespace'::OnNoMemory()  Line 126	C++
	chrome.dll!_invalid_parameter_noinfo()  Line 99 + 0xc bytes	C++
	chrome.dll!RefCountedBytes::front()  Line 67 + 0x1b bytes	C++
	chrome.dll!BookmarkModel::OnFavIconDataAvailable(int handle=8, bool know_favicon=true, scoped_refptr<RefCountedBytes> data={...}, bool expired=true, GURL icon_url={...})  Line 652 + 0x2b bytes	C++

It seems RefCountedBytes data has no data. If data size is 0, accessing front
of data would cause crash.
By checking its size, fixes this crash.

BUG=25803
TEST=no crash on startup

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=30171

[tkent, 2009-10-27 05:39:07]

LGTM

[sky, 2009-10-27 16:07:03]

There are a couple of other places in code that have the same pattern. Those
should be fixed too.

http://codereview.chromium.org/328037/diff/1/2
File chrome/browser/bookmarks/bookmark_model.cc (right):

http://codereview.chromium.org/328037/diff/1/2#newcode651
Line 651: if (know_favicon && data.get() && data->size() &&
nit: !data->data.empty()

[sky, 2009-10-27 16:10:11]

Looks like Brett fixed the source of the problem. See
http://codereview.chromium.org/333048 .