Change NaCl IPC PPAPI proxy startup to support a NaCl-Browser process

Change NaCl IPC PPAPI proxy startup to support a NaCl-Browser process
channel.

NaClProcessHost now creates an initial NaCl-Browser channel, then uses
it to send a message to create the NaCl-Renderer channel. The main() for
the IPC-IRT creates a PpapiDispatcher object to manage this channel and
manage the PluginDispatchers for each renderer.
BUG=116317
TEST=manual
TBR=bbudge@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=154231

[bbudge, 2012-08-30 17:16:25]

I had to revert this because of ARM build failures. I'm adding back the flag for
C++ 11 extensions to be turned off for now. There's no need to review this
(unless you want to!). I'll TBR it to me so I can reland.

[dmichael (off chromium), 2012-08-30 17:50:41]

http://codereview.chromium.org/10912011/diff/1/build/common_untrusted.gypi
File build/common_untrusted.gypi (right):

http://codereview.chromium.org/10912011/diff/1/build/common_untrusted.gypi#ne...
build/common_untrusted.gypi:26: # TODO(bbudge) Figure out why above 'clang = 1'
doesn't fix this.
I'm not a gyp-spert...  but should this whole 'conditions' section be inside
variables? I would have expected 'defines' and 'compile_flags' at least to be
outside of variables, with variables inside 'conditions' (instead of the other
way around). And then, I suspect:
'clang': 1
would go inside the variables section?