Expose an API on ArrayBufferView to copy out content w/o changing the buffer

Expose an API on ArrayBufferView to copy out content w/o changing the buffer

BUG=v8:3996
LOG=y
R=dslomov@chromium.org,kbr@chromium.org,hpayer@chromium.org

Committed: https://crrev.com/2a5eb8299b2fa13d57d1d4741d4f121df1c3e883
Cr-Commit-Position: refs/heads/master@{#27580}

[jochen (gone - plz use gerrit), 2015-03-31 16:39:15]

ptal

[jochen (gone - plz use gerrit), 2015-03-31 16:40:27]

https://codereview.chromium.org/1041403003/diff/40001/test/cctest/test-typeda...
File test/cctest/test-typedarrays.cc (right):

https://codereview.chromium.org/1041403003/diff/40001/test/cctest/test-typeda...
test/cctest/test-typedarrays.cc:47: "var a = new Uint8Array(4);"
this is actually the only case that creates an on-v8-heap typed array

[Dmitry Lomov (no reviews), 2015-04-01 08:48:57]

https://codereview.chromium.org/1041403003/diff/40001/src/api.cc
File src/api.cc (right):

https://codereview.chromium.org/1041403003/diff/40001/src/api.cc#newcode6430
src/api.cc:6430: size_t byte_offset =
static_cast<size_t>(obj->byte_offset()->Number());
Use NumberToSize function

https://codereview.chromium.org/1041403003/diff/40001/src/api.cc#newcode6432
src/api.cc:6432: i::Min(byte_length,
static_cast<size_t>(obj->byte_length()->Number()));
Use NumberToSize function

https://codereview.chromium.org/1041403003/diff/40001/src/api.cc#newcode6434
src/api.cc:6434: const char* source = nullptr;
Since you operate with raw pointers into V8 heap, use DisallowHeapAllocation to
make sure no gc happens

[jochen (gone - plz use gerrit), 2015-04-02 08:20:03]

ptal

[Dmitry Lomov (no reviews), 2015-04-02 09:34:20]

lgtm

[jochen (gone - plz use gerrit), 2015-04-02 09:34:56]

The CQ bit was checked by jochen@chromium.org

[commit-bot: I haz the power, 2015-04-02 09:35:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1041403003/80001

[commit-bot: I haz the power, 2015-04-02 09:36:42]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2015-04-02 09:36:55]

Patchset 5 (id:??) landed as
https://crrev.com/2a5eb8299b2fa13d57d1d4741d4f121df1c3e883
Cr-Commit-Position: refs/heads/master@{#27580}