Don't do work in the SharedIOBuffer constructor; use an Init method instead. ...

Don't do work in the SharedIOBuffer constructor; use an Init method instead. This eliminates instances of allocated-but-invalid SharedIOBuffers. Also clean up some CHECKs and TODOs associated with the bug.

The upshot is that we no longer crash in AsyncResourceHandler::OnResponseCompleted() when we can't allocate shared memory. We now crash (properly, I believe) in the renderer process if the shared memory that failed to allocate was the TransportDIB, since the renderer can't communicate with the browser without it.

BUG=16371
TEST=none

[willchan no longer on Chromium, 2009-11-17 17:13:06]

How does this affect the Linux case when the users have incorrect permissions
set on /dev/shm, so we can't map shared memory there?  If you look at comment 10
on bug 16371, SharedIOBuffer::ok() had returned true (which is the equivalent of
your SharedIOBuffer::Init() return value), yet we still hit the CHECK on the
next line, and thus crash in the browser process.

[hawk, 2009-11-18 22:36:25]

On 2009/11/17 17:13:06, willchan wrote:
> How does this affect the Linux case when the users have incorrect permissions
> set on /dev/shm, so we can't map shared memory there?  If you look at comment
10
> on bug 16371, SharedIOBuffer::ok() had returned true (which is the equivalent
of
> your SharedIOBuffer::Init() return value), yet we still hit the CHECK on the
> next line, and thus crash in the browser process.

You're right, I've added the CHECKs back in, as this doesn't address that issue.
I've left in the new Init() method, which does address the issues on Mac OS X
with insufficient disk space and inability to find a writable temp directory.
The problem there was that the read_buffer_ object was allocated but pointed to
NULL because it couldn't create the shared memory. Later,
AsyncResourceHandler::OnResponseCompleted() was called and
CHECK(read_buffer_->data()) was hit. Now read_buffer_ is correctly NULL when
AsyncResourceHandler::OnResponseCompleted() is called.

I added a CHECK to the Init() method to see if shared_memory_.Create() and
shared_memory_.Map() are returning true even though shared_memory_.memory()
returns NULL. If we hit it, that could explain the comment 10 behavior.

[willchan no longer on Chromium, 2009-11-19 17:22:58]

LGTM