Mojo: DataPipe: Write some docs and rationalize some return values.

In "all or none" mode, return "out of range" if the required amount of
space/data isn't available, unless the other end isn't open (in which
case return "failed precondition"). Don't return "should wait", since
you can't wait for a specified amount of space/data to be available.
(Only return "should wait" when waiting would actually solve your
problem.)

Note: Still have to write docs for the two-phase DataPipe APIs (but I
want to fully test/hash out their semantics first).

R=darin@chromium.org

Review URL: https://codereview.chromium.org/118873004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243327 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243327
Make sdch not use an incompatible stdint.h.

We force-include our own logging.h, which includes basictypes.h, which
now includes stdint.h. Without this change, this ends up being
minimal/hacky stdint.h (from sdch/open-vcdiff/vsprojects), which isn't
sufficient for the needs of the rest of basictypes.h.

R=brettw@chromium.org, jar@chromium.org
BUG=138542

Review URL: https://codereview.chromium.org/110273004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243329 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243329