Further clean up pepper's use of SharedMemory.

Further clean up pepper's use of SharedMemory.

This CL uses the new methods content::BrokerDuplicateSharedMemoryHandle() and
base::SharedMemory::DuplicateHandle() to remove some duplicated code. This CL
changes the implementation of ShareSharedMemoryhandleWithRemote() to no longer
assume that the SharedMemoryHandle is backed by a POSIX fd.

BUG=466437
Committed: https://crrev.com/fc29ad99d6286026e7cce6019179334d59330935
Cr-Commit-Position: refs/heads/master@{#332903}

[erikchen, 2015-06-03 04:52:13]

The CQ bit was checked by erikchen@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-06-03 04:52:52]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1166443004/40001

[commit-bot: I haz the power, 2015-06-03 06:28:43]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-06-03 06:28:45]

Dry run: Try jobs failed on following builders:
  win8_chromium_rel on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win8_chromium_rel...)

[erikchen, 2015-06-03 17:33:00]

The CQ bit was checked by erikchen@chromium.org to run a CQ dry run

[erikchen, 2015-06-03 17:33:51]

erikchen@chromium.org changed reviewers:
+ piman@chromium.org

[erikchen, 2015-06-03 17:33:52]

piman: Please review.

[commit-bot: I haz the power, 2015-06-03 17:35:31]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1166443004/60001

[piman, 2015-06-03 17:44:45]

LGTM+nits

https://codereview.chromium.org/1166443004/diff/60001/content/ppapi_plugin/pp...
File content/ppapi_plugin/ppapi_thread.cc (right):

https://codereview.chromium.org/1166443004/diff/60001/content/ppapi_plugin/pp...
content/ppapi_plugin/ppapi_thread.cc:214: base::SharedMemoryHandle duped_handle;
nit: just initialize this with base::SharedMemory::NULLHandle() and return it
unconditionally?

https://codereview.chromium.org/1166443004/diff/60001/content/renderer/pepper...
File content/renderer/pepper/pepper_proxy_channel_delegate_impl.cc (right):

https://codereview.chromium.org/1166443004/diff/60001/content/renderer/pepper...
content/renderer/pepper/pepper_proxy_channel_delegate_impl.cc:43:
base::SharedMemoryHandle duped_handle;
nit: just initialize this with base::SharedMemory::NULLHandle() and return it
unconditionally?

[erikchen, 2015-06-03 17:58:32]

https://codereview.chromium.org/1166443004/diff/60001/content/ppapi_plugin/pp...
File content/ppapi_plugin/ppapi_thread.cc (right):

https://codereview.chromium.org/1166443004/diff/60001/content/ppapi_plugin/pp...
content/ppapi_plugin/ppapi_thread.cc:214: base::SharedMemoryHandle duped_handle;
On 2015/06/03 17:44:44, piman (Very slow to review) wrote:
> nit: just initialize this with base::SharedMemory::NULLHandle() and return it
> unconditionally?

Your suggestion saves 3 lines of code, but it makes the assumption that if
BrokerDuplicateSharedMemoryHandle fails, it will not touch duped_handle. (Having
looked through the current implementation, I think this is true, although it
depends on implementation of Windows's DuplicateHandle() function, and I'm
generally not inclined to trust anything developed by Microsoft.)

I think that the current code more clearly reflects the semantics of
BrokerDuplicateSharedMemoryHandle(). Are you okay with the current
implementation?

[commit-bot: I haz the power, 2015-06-03 18:50:20]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-06-03 18:50:21]

Dry run: Try jobs failed on following builders:
  linux_chromium_asan_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[erikchen, 2015-06-04 19:47:43]

On 2015/06/03 18:50:21, commit-bot: I haz the power wrote:
> Dry run: Try jobs failed on following builders:
>   linux_chromium_asan_rel_ng on tryserver.chromium.linux (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

piman: Ping.

I'm sending the CL as is to the CQ, without addressing your nits. If you don't
like my response in #10, feel free to speak up and I'll upload a new CL that
changes the structure of the code to match your suggestion.

[erikchen, 2015-06-04 19:48:01]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-06-04 19:49:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1166443004/60001

[commit-bot: I haz the power, 2015-06-04 20:44:24]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-06-04 20:45:25]

Patchset 4 (id:??) landed as
https://crrev.com/fc29ad99d6286026e7cce6019179334d59330935
Cr-Commit-Position: refs/heads/master@{#332903}