Fix local reference leak in OpenApkAsset.
Fix local reference leak in OpenApkAsset.

OpenApkAsset was incorrectly calling ScopedJavaLocalRef::Release on the
name of the asset, causing the local reference to leak. This doesn't
matter a great deal in most cases since local references are cleaned up
when returning to Java, but for running native unittest APKs this gets
called once per test and so it's possible for the local reference table
to fill up in some cases.

Call obj() instead to get a temporary reference to the jobject, so that
the reference is still deleted once it goes out of scope.

BUG=516725

Review URL: https://codereview.chromium.org/1272203002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#341906}

axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,Chilledheart/chromium,Chilledheart/chromium,Chilledheart/chromium,Chilledheart/chromium,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,Chilledheart/chromium,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,Just-D/chromium-1,Just-D/chromium-1,Just-D/chromium-1,Chilledheart/chromium,axinging/chromium-crosswalk,Chilledheart/chromium,axinging/chromium-crosswalk,axinging/chromium-crosswalk