Add the plumbing and test code for plugins opening files from the sandbox. Th...

Add the plumbing and test code for plugins opening files from the sandbox. This
does not implement the actual opening of the files (currently the chain ends in
resource_message_filter.cc), I will do that separately with some additional
security review. This current patch just gets the synchronous request to the
browser and returns a NULL result.

TEST=none
BUG=none

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=30819

[jam, 2009-10-30 23:24:58]

lgtm

http://codereview.chromium.org/340050/diff/15/1022
File chrome/browser/renderer_host/resource_message_filter.cc (right):

http://codereview.chromium.org/340050/diff/15/1022#newcode1176
Line 1176: //
note: when this is implemented, please ensure that the file opening happens on
the file thread.  In which case you want to use IPC_MESSAGE_HANDLER_DELAY_REPLY.
 I'm checking in a change right now which makes it trivial to go to the file
loop and back without running into issues of where the ref counted object gets
destructed (http://codereview.chromium.org/338065)

http://codereview.chromium.org/340050/diff/15/1026
File chrome/renderer/webplugin_delegate_pepper.cc (right):

http://codereview.chromium.org/340050/diff/15/1026#newcode464
Line 464: if (!result.file_handle)
might be clearer to check both file_handle and the result of Send?

[darin (slow to review), 2009-10-31 22:42:14]

what policy will we use for deciding what files to open in response to this IPC?
 (we don't want to allow the renderer to open any file, right?)