Implement basic crash detection and shutdown handling for out of process PPAP...

Implement basic crash detection and shutdown handling for out of process PPAPI
plugins.

Currently when a crash is detected we just delete as much stuff as is
convenient, clear the plugin's backing store, and continue running. It does not
hook up a sad plugin page yet.

This adds a "proxy" interface for the proxy to tell the PPAPI backend
implementation in the renderer about proxy-related stuff (like the plugin
crashing).

This also implements keeping the process alive for a period of time so we can
re-use the same process.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=74965

[brettw, 2011-02-14 23:00:05]

http://codereview.chromium.org/6493004/diff/1/webkit/plugins/ppapi/resource_t...
File webkit/plugins/ppapi/resource_tracker.cc (right):

http://codereview.chromium.org/6493004/diff/1/webkit/plugins/ppapi/resource_t...
webkit/plugins/ppapi/resource_tracker.cc:164: DLOG_IF(ERROR,
!CheckIdType(instance, PP_ID_TYPE_INSTANCE))
This code just moved from above with no changes except the one line marked
below.

http://codereview.chromium.org/6493004/diff/1/webkit/plugins/ppapi/resource_t...
webkit/plugins/ppapi/resource_tracker.cc:216: if (delete_instance)
This if statement was added.

[jam, 2011-02-14 23:08:29]

lgtm

http://codereview.chromium.org/6493004/diff/1/chrome/ppapi_plugin/plugin_proc...
File chrome/ppapi_plugin/plugin_process_dispatcher.cc (right):

http://codereview.chromium.org/6493004/diff/1/chrome/ppapi_plugin/plugin_proc...
chrome/ppapi_plugin/plugin_process_dispatcher.cc:19: const int
kPluginReleaseTimeMS = 30 * 1000;  // 30 seconds.
nit: most of the code uses Ms