Make StackContainer test pass on Android.

Make StackContainer test pass on Android.

Failure output from experimental Android builder:
[ RUN      ] StackContainer.BufferAlignment
base/stack_container_unittest.cc:126: Failure
Value of: reinterpret_cast<uintptr_t>(&aligned256[0]) & (256 - 1)
  Actual: 80
Expected: 0u
Which is: 0
[  FAILED  ] StackContainer.BufferAlignment (1 ms)

BUG=115612
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=124126

[David Trainor- moved to gerrit, 2012-02-23 23:34:47]

lgtm

[willchan no longer on Chromium, 2012-02-24 00:18:14]

Doesn't this mean that it's unsafe to use StackContainer<T> where sizeof(T) >
16? Perhaps you should add a COMPILE_ASSERT for OS_ANDROID.

[jbates, 2012-02-27 18:07:44]

On 2012/02/24 00:18:14, willchan wrote:
> Doesn't this mean that it's unsafe to use StackContainer<T> where sizeof(T) >
> 16? 

I think Android is still running on devices with at most 16 byte registers
(NEON), so alignments of more than 16 would only affect performance unless it
were done in driver code where full cacheline alignment may be required to
communicate with a device.

>Perhaps you should add a COMPILE_ASSERT for OS_ANDROID.

Done. This way we'll at least know when someone attempts more than 16 byte
alignment on Android.

[willchan no longer on Chromium, 2012-02-28 22:31:08]

LGTM

http://codereview.chromium.org/9456032/diff/5001/base/stack_container.h
File base/stack_container.h (right):

http://codereview.chromium.org/9456032/diff/5001/base/stack_container.h#newco...
base/stack_container.h:56: #if defined(OS_ANDROID)
Do we need to include build/build_config.h to get this?

[jbates, 2012-02-28 22:52:13]

https://chromiumcodereview.appspot.com/9456032/diff/5001/base/stack_container.h
File base/stack_container.h (right):

https://chromiumcodereview.appspot.com/9456032/diff/5001/base/stack_container...
base/stack_container.h:56: #if defined(OS_ANDROID)
On 2012/02/28 22:31:08, willchan wrote:
> Do we need to include build/build_config.h to get this?

Done.

[commit-bot: I haz the power, 2012-02-28 22:52:29]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jbates@chromium.org/9456032/9001

[commit-bot: I haz the power, 2012-02-28 23:20:49]

Try job failure for 9456032-9001 (retry) on linux_clang for step "compile"
(clobber build).
It's a second try, previously, step "compile" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_clan...

[commit-bot: I haz the power, 2012-02-28 23:25:13]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jbates@chromium.org/9456032/12004

[commit-bot: I haz the power, 2012-02-29 05:46:36]

Change committed as 124126