Fix clip_span() to use memmove() instead of memcpy().

Fix clip_span() to use memmove() instead of memcpy().
This is actually a merge of upstream commit a44d715d2b19dc2f8f48b01144cc38e4e2c5015a

BUG=139587, 132211
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=149148

[Alexander Potapenko, 2012-07-30 12:04:06]

Ken, Al, can you please take a look?
This patch is likely to fix a big number of ASan reports on the Webkit Linux
ASan bot
(http://build.chromium.org/p/chromium.webkit/builders/Webkit%20Linux%20ASAN)

[Alexander Potapenko, 2012-07-30 12:07:40]

On 2012/07/30 12:04:06, Alexander Potapenko wrote:
> Ken, Al, can you please take a look?
> This patch is likely to fix a big number of ASan reports on the Webkit Linux
> ASan bot
>
(http://build.chromium.org/p/chromium.webkit/builders/Webkit%2520Linux%2520ASAN)

That's
http://build.chromium.org/p/chromium.webkit/builders/Webkit%20Linux%20ASAN

[Ken Russell (switch to Gerrit), 2012-07-30 18:30:18]

Nice fix. LGTM

Could you please update third_party/mesa/README.chromium at least to indicate
this patch and point to this code review? It's a real pain to regenerate
chromium.patch so don't worry about that. (Additionally, the version of Mesa
Chrome uses is really old, so the patch would not be that useful at this point.)

[Ken Russell (switch to Gerrit), 2012-07-30 18:31:32]

Also, if you wouldn't mind, please check out the current Mesa sources and see
whether this issue still exists there. If it does, please file a bug with them.
http://mesa3d.org/

[Alexander Potapenko, 2012-07-31 08:15:57]

On 2012/07/30 18:31:32, kbr wrote:
> Also, if you wouldn't mind, please check out the current Mesa sources and see
> whether this issue still exists there. If it does, please file a bug with
them.
> http://mesa3d.org/

Looks like they're using memmove in 8.0.4:
http://cgit.freedesktop.org/mesa/mesa/tree/src/mesa/swrast/s_span.c?id=mesa-8...

[Alexander Potapenko, 2012-07-31 08:30:08]

I've updated the CL description and the README file to reflect the fact this is
actually a merge from upstream Mesa. Committing the change.