Simplify DoParseProgram

Simplify DoParseProgram

DoParseProgram doesn't appear to need to receive toplevel scopes as
arguments; it can properly set the end_position of the scopes to the
scanner's position after parsing is complete.

R=marja@chromium.org
BUG=
LOG=N

Committed: https://crrev.com/e0913eccfbe6809a7a00af43d90aad28a430f80b
Cr-Commit-Position: refs/heads/master@{#27880}

[wingo, 2015-04-16 09:01:58]

The reason that this patch changed layout expectations could be that
scanner().location().end_pos is not the same as source->length() when parsing
from a string "source".  I added a local CHECK about this and indeed, indeed.  I
guess these should be the same, so I'll see what I can do.

[wingo, 2015-04-16 09:31:07]

Patch 1 is exactly what was landed in
https://codereview.chromium.org/1058363003.    The update uses the
peek_location().beg_pos to mark the scope end, as the parser will peek but not
consume EOS.  It also adds a dcheck that peek_location().beg_pos is equal to the
source string length, when parsing from a string.

This may change layout tests for streaming parsing, but hopefully not.  I guess
we'll see.  WDYT Marja?

[marja, 2015-04-16 09:39:06]

lgtm if the new tryjob is happy

[wingo, 2015-04-16 09:40:25]

On 2015/04/16 09:39:06, marja wrote:
> lgtm if the new tryjob is happy

fwiw the previous one failed due to lack of -lX11 or something strange

/usr/bin/ld: cannot find -lX11
/usr/bin/ld: cannot find -lXi
clang: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.

[marja, 2015-04-16 09:42:22]

Ähm, me. machenbach@, what's up with that bot?

wingo: why would this change the result for streaming parsing?

[marja, 2015-04-16 09:43:56]

*meh

Btw, there are no layout tests for streaming afaics, but it should be tested w/
cctest... not sure though if those would notice if the scope end position
changes! If you're suspecting there might be some changes, pls add tests there.

[wingo, 2015-04-16 09:44:49]

On 2015/04/16 09:42:22, marja wrote:
> Ähm, me. machenbach@, what's up with that bot?
> 
> wingo: why would this change the result for streaming parsing?

It could change the result for streaming because ParseOnBackground was calling
scope->set_end_position(scanner()->location().end_pos), and this patch changes
to use peek_location().beg_pos.  But I don't know if this would cause any change
visible to the test suite.

[marja, 2015-04-16 09:49:55]

Hmm, so the end positions were inconsistent before, right? (source->length() for
the non-streaming version, which is the same as
scanner_.peek_location().beg_pos), and scanner()->location().end_pos for
streaming. That was probably unintentional - this change should be good anyway!
:)

[marja, 2015-04-16 09:50:27]

(So you can land if you've ran the layout tests yourself.)

[wingo, 2015-04-16 12:13:15]

The CQ bit was checked by wingo@igalia.com

[commit-bot: I haz the power, 2015-04-16 12:13:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1091743002/20001

[commit-bot: I haz the power, 2015-04-16 12:42:47]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-16 12:43:01]

Patchset 2 (id:??) landed as
https://crrev.com/e0913eccfbe6809a7a00af43d90aad28a430f80b
Cr-Commit-Position: refs/heads/master@{#27880}