[WebMIDI] Fix a WebMIDIPermissionRequest leak.

[WebMIDI] Fix a WebMIDIPermissionRequest leak.

IDMap<T, OS> owns its values only if OS == IDMapOwnPtr.

BUG=NONE
R=toyoshim@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=276614

[Takashi Toyoshima, 2014-06-11 04:24:56]

lgtm.
thank you for catching this.

[yhirano, 2014-06-11 04:50:18]

+dalecurtis for OWNER review.

[DaleCurtis, 2014-06-11 21:22:23]

lgtm

[yhirano, 2014-06-11 23:56:08]

The CQ bit was checked by yhirano@chromium.org

[commit-bot: I haz the power, 2014-06-11 23:57:10]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/yhirano@chromium.org/323083002/20001

[commit-bot: I haz the power, 2014-06-12 04:47:19]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  ios_dbg_simulator on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_dbg_simulator/bui...)
  ios_rel_device on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_rel_device/builds...)
  ios_rel_device_ninja on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_rel_device_ninja/...)
  mac_chromium_compile_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_compile_...)
  mac_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_rel/buil...)
  win_chromium_compile_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_compile_...)
  win_chromium_x64_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_x64_rel/...)

[commit-bot: I haz the power, 2014-06-12 10:13:32]

Change committed as 276614