Linux: refactor zygote support

http://code.google.com/p/chromium/wiki/LinuxZygote

  * Move Chrome specific bits out of base
  * Move away from the idea of reserved file descriptors (which don't really work
  with zygotes)
  * Load resources before forking renderers (means that we don't need
  communication between the zygote process and the renderers)
  * Make sure that gdb works against the browser again
  * Make sure that we have different ASLR between the renderers and the browser.

http://codereview.chromium.org/119335

(This is a reland. First landed in r18109, reverted in r18112.)


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@18291 0039d316-1c4b-4281-b951-d872f2087c98

• base/base.gyp[diff]
• base/command_line.cc[diff]
• base/command_line.h[diff]
• base/file_util_posix.cc[diff]
• base/global_descriptors_posix.cc[Added - diff]
• base/global_descriptors_posix.h[Added - diff]
• base/logging.cc[diff]
• base/process_util.h[diff]
• base/process_util_linux.cc[diff]
• base/reserved_file_descriptors.h[Deleted - diff]
• base/unix_domain_socket_posix.cc[Added - diff]
• base/unix_domain_socket_posix.h[Added - diff]
• base/zygote_manager.cc[Deleted - diff]
• base/zygote_manager.h[Deleted - diff]
• chrome/app/breakpad_linux.cc[diff]
• chrome/app/chrome_dll_main.cc[diff]
• chrome/app/chrome_main_uitest.cc[diff]
• chrome/browser/plugin_process_host.cc[diff]
• chrome/browser/renderer_host/browser_render_process_host.cc[diff]
• chrome/browser/renderer_host/browser_render_process_host.h[diff]
• chrome/browser/zygote_host_linux.cc[Added - diff]
• chrome/browser/zygote_host_linux.h[Added - diff]
• chrome/browser/zygote_main_linux.cc[Added - diff]
• chrome/chrome.gyp[diff]
• chrome/common/chrome_descriptors.h[Added - diff]
• chrome/common/chrome_switches.cc[diff]
• chrome/common/chrome_switches.h[diff]
• chrome/common/ipc_channel.h[diff]
• chrome/common/ipc_channel_posix.cc[diff]
• chrome/common/ipc_channel_posix.h[diff]
• chrome/common/ipc_channel_proxy.cc[diff]
• chrome/common/ipc_channel_proxy.h[diff]
• chrome/common/ipc_tests.cc[diff]
• chrome/common/process_watcher_posix.cc[diff]
• chrome/plugin/plugin_main.cc[diff]
• chrome/renderer/renderer_main_unittest.cc[diff]
• chrome/test/automation/automation_proxy.cc[diff]
• chrome/test/chrome_process_util.cc[diff]