Revert of Some inline ARM assembly for saturated arithmetic, a small speed-up for

Revert of Some inline ARM assembly for saturated arithmetic, a small speed-up for (https://codereview.chromium.org/346913004/)

Reason for revert:
Looks like this isn't compiling on android_clang_dbg (needed for the roll into chromium); reverting for now.

http://build.chromium.org/p/tryserver.chromium/builders/android_clang_dbg/builds/157031/steps/compile/logs/stdio

Original issue's description:
> Some inline ARM assembly for saturated arithmetic and a small speed-up
> for the C version of saturated add and subtract. Created a unit test for
> setting a saturated value.
> 
> Benchmarking using rasterize_and_record_micro.key_mobile_sites on a
> Nexus7 recorded a consistent drop in RasterizeAndRecordMicro:record_time
> from 5.18ms to 4.93ms (~5% improvement).
> 
> BUG=325746
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177208

TBR=bulach@chromium.org,skyostil@chromium.org,schenney@chromium.org,picksi@google.com,eseidel@chromium.org,eae@chromium.org,picksi@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=325746
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177212

[Timothy Loh, 2014-06-30 13:57:13]

Created Revert of Some inline ARM assembly for saturated arithmetic, a small
speed-up for

[commit-bot: I haz the power, 2014-06-30 13:57:58]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/timloh@chromium.org/337323004/1

[commit-bot: I haz the power, 2014-06-30 13:58:28]

Change committed as 177212