Remove calls to HandleScope default ctor.

Remove calls to HandleScope default ctor.

It's replaced by a version which takes an isolate. The default ctor will be removed soon.

BUG=
R=jamesr@chromium.org, sky@chromium.org, szym@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=221193

[marja, 2013-09-02 08:53:38]

james, sky, szym: ptal, here's some more V8 bindings related clean up.

jamesr:
content/renderer/browser_plugin/browser_plugin.cc
content/renderer/pepper/message_channel.cc
content/renderer/pepper/v8_var_converter.cc
content/renderer/render_view_impl.cc
content/renderer/v8_value_converter_impl.cc

sky:
content/public/test/render_view_test.cc

szym:
net/proxy/proxy_resolver_v8.cc

[szym, 2013-09-02 19:52:28]

net LGTM

[sky, 2013-09-03 16:17:03]

LGTM

[jamesr, 2013-09-03 21:23:28]

lgtm

[commit-bot: I haz the power, 2013-09-04 06:48:34]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/marja@chromium.org/23861002/3001

[marja, 2013-09-04 16:11:19]

Committed patchset #3 manually as r221193 (presubmit successful).