IndexedDB: continuePrimaryKey() on object store cursor should throw

IndexedDB: continuePrimaryKey() on object store cursor should throw

Behind the --enable-experimental-web-platform-features flag, Blink
supports a new continuePrimaryKey() method on IDBCursor. This is
intended for use on indexes to advance a cursor to a specific (key,
primaryKey) pair. It's not fully specified yet only hashed out in
bugs[1] (hence, experimental). Calling the method on a cursor which
has an object store rather than an index as its source hits a DCHECK.

Pending a full spec for the feature, have the method throw if the
cursor's source is not an index.

[1] https://github.com/w3c/IndexedDB/issues/14

R=cmumford@chromium.org
BUG=493443
TEST=idbcursor_continueprimarykey.html

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196108

[jsbell, 2015-05-28 23:51:39]

cmumford@ - please take a look?

[cmumford, 2015-05-29 00:32:17]

lgtm

https://codereview.chromium.org/1160853004/diff/1/LayoutTests/storage/indexed...
File LayoutTests/storage/indexeddb/idbcursor_continueprimarykey.html (right):

https://codereview.chromium.org/1160853004/diff/1/LayoutTests/storage/indexed...
LayoutTests/storage/indexeddb/idbcursor_continueprimarykey.html:22:
assert_true(cursor instanceof IDBCursor,
assert_class_string

[jsbell, 2015-05-29 00:35:03]

The CQ bit was checked by jsbell@chromium.org

[jsbell, 2015-05-29 00:35:03]

The patchset sent to the CQ was uploaded after l-g-t-m from
cmumford@chromium.org
Link to the patchset: https://codereview.chromium.org/1160853004/#ps20001
(title: "eschew assert_true")

[jsbell, 2015-05-29 00:35:12]

https://codereview.chromium.org/1160853004/diff/1/LayoutTests/storage/indexed...
File LayoutTests/storage/indexeddb/idbcursor_continueprimarykey.html (right):

https://codereview.chromium.org/1160853004/diff/1/LayoutTests/storage/indexed...
LayoutTests/storage/indexeddb/idbcursor_continueprimarykey.html:22:
assert_true(cursor instanceof IDBCursor,
On 2015/05/29 00:32:17, cmumford wrote:
> assert_class_string

Done.

[commit-bot: I haz the power, 2015-05-29 00:35:29]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1160853004/20001

[commit-bot: I haz the power, 2015-05-29 01:54:06]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196108