Deal with extension loading from packages.

Deal with extension loading from packages.

The issue is bad interplay with package and dart-ext URIs.
dart-ext URIs overwrite the package URI which makes us lose
the package URI path components. This change resolves
all the way to a file path for dart-ext URIs if the base
URI is a package URI.

R=whesse@google.com
BUG=dartbug.com/6264

Committed: https://code.google.com/p/dart/source/detail?r=15272

[Bill Hesse, 2012-11-22 16:18:41]

LGTM.

https://codereview.chromium.org/11308170/diff/1/runtime/bin/extensions.cc
File runtime/bin/extensions.cc (right):

https://codereview.chromium.org/11308170/diff/1/runtime/bin/extensions.cc#new...
runtime/bin/extensions.cc:18: 
Do we really want unchecked malloc (strdup) to go ahead to a null pointer error?
 Is that the accepted failure for out of C++ heap memory?

[Mads Ager (google), 2012-11-23 07:07:39]

https://codereview.chromium.org/11308170/diff/1/runtime/bin/extensions.cc
File runtime/bin/extensions.cc (right):

https://codereview.chromium.org/11308170/diff/1/runtime/bin/extensions.cc#new...
runtime/bin/extensions.cc:18: 
On 2012/11/22 16:18:41, Bill Hesse wrote:
> Do we really want unchecked malloc (strdup) to go ahead to a null pointer
error?
>  Is that the accepted failure for out of C++ heap memory?

It would be nicer to deal with it although in general there is little you can do
if a strdup of a short string fails. In that case the next step will probably
fail as well so crashing in a controlled way is usually they best you can do.
I'll restore the null pointer check in this particular case.