Add Cast() for Int32 and Uint32

Add Cast() for Int32 and Uint32

It should be possible to cast a Value to Int32 without throwing an exception
when IsInt32() is true. Same for Uint32.

BUG=chromium:462402
LOG=Y

Committed: https://crrev.com/83245abb6b6503772f39625025d64caef84b513f
Cr-Commit-Position: refs/heads/master@{#27156}

[bashi, 2015-03-12 10:37:10]

bashi@chromium.org changed reviewers:
+ dcarney@chromium.org

[bashi, 2015-03-12 10:37:11]

Here are some contexts:
https://codereview.chromium.org/993333002/#msg5
https://codereview.chromium.org/873983003/

In short, I think it's OK to add Cast() to Int32 and Uint32 and it will
make Blink and other embedders happy (less empty checks). WDYT?

[dcarney, 2015-03-12 10:45:58]

https://codereview.chromium.org/1003663002/diff/1/src/api.cc
File src/api.cc (right):

https://codereview.chromium.org/1003663002/diff/1/src/api.cc#newcode2678
src/api.cc:2678: bool Value::IsInt32() const { return
Utils::OpenHandle(this)->IsInt32(); }
i don't think v8 cares internally about this distinction, there's no reason to
push this to objects.cc

https://codereview.chromium.org/1003663002/diff/1/src/api.cc#newcode2681
src/api.cc:2681: bool Value::IsUint32() const { return
Utils::OpenHandle(this)->IsUint32(); }
same

https://codereview.chromium.org/1003663002/diff/1/src/api.cc#newcode2960
src/api.cc:2960: Utils::ApiCheck(obj->IsInt32(), "v8::Int32::Cast()",
just use that->IsInt32()

https://codereview.chromium.org/1003663002/diff/1/src/api.cc#newcode2966
src/api.cc:2966: i::Handle<i::Object> obj = Utils::OpenHandle(that);
same

[bashi, 2015-03-12 12:19:19]

Thank you for review!

https://codereview.chromium.org/1003663002/diff/1/src/api.cc
File src/api.cc (right):

https://codereview.chromium.org/1003663002/diff/1/src/api.cc#newcode2678
src/api.cc:2678: bool Value::IsInt32() const { return
Utils::OpenHandle(this)->IsInt32(); }
On 2015/03/12 10:45:58, dcarney wrote:
> i don't think v8 cares internally about this distinction, there's no reason to
> push this to objects.cc

Right. Reverted.

https://codereview.chromium.org/1003663002/diff/1/src/api.cc#newcode2960
src/api.cc:2960: Utils::ApiCheck(obj->IsInt32(), "v8::Int32::Cast()",
On 2015/03/12 10:45:58, dcarney wrote:
> just use that->IsInt32()

Done.

[dcarney, 2015-03-12 12:25:52]

lgtm

[bashi, 2015-03-12 12:26:25]

The CQ bit was checked by bashi@chromium.org

[commit-bot: I haz the power, 2015-03-12 12:26:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1003663002/20001

[commit-bot: I haz the power, 2015-03-12 12:27:46]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-03-12 12:27:53]

Patchset 2 (id:??) landed as
https://crrev.com/83245abb6b6503772f39625025d64caef84b513f
Cr-Commit-Position: refs/heads/master@{#27156}