Enable about:nacl and correct symbol visibility for the plugin

Enable about:nacl and correct symbol visibility for the plugin

After this change, if libppGoogleNaClPluginChrome.so is placed in the install
directory it correctly starts and attempts to create a subprocess.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3032
R=bradnelson@google.com, darin@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=276724

[sehr, 2014-06-11 21:29:22]

One more small step.  I need to get packaging and process creation working.

[bradn, 2014-06-11 21:42:02]

lgtm

[darin (slow to review), 2014-06-11 21:49:51]

LGTM

[sehr, 2014-06-11 23:37:53]

The CQ bit was checked by sehr@chromium.org

[commit-bot: I haz the power, 2014-06-11 23:38:45]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/sehr@chromium.org/329853002/1

[commit-bot: I haz the power, 2014-06-12 01:07:01]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  ios_dbg_simulator on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_dbg_simulator/bui...)
  ios_rel_device on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_rel_device/builds...)
  ios_rel_device_ninja on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_rel_device_ninja/...)
  mac_chromium_compile_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_compile_...)
  mac_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_rel/buil...)
  win_chromium_compile_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_compile_...)
  win_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_rel/buil...)
  win_chromium_x64_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_x64_rel/...)
  mac_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/mac_gpu/builds/15780)
  win_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu/builds/18912)

[commit-bot: I haz the power, 2014-06-12 02:17:10]

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

[commit-bot: I haz the power, 2014-06-12 02:17:11]

Try jobs failed on following builders:
  win_chromium_compile_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_compile_...)
  win_chromium_x64_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_x64_rel/...)

[sehr, 2014-06-12 17:21:03]

Committed patchset #1 manually as r276724 (presubmit successful).