Revert of Minor changes to allow Pepper InstancePrivate tests to pass with gin

Revert of Minor changes to allow Pepper InstancePrivate tests to pass with gin (patchset #3 of https://codereview.chromium.org/472693002/)

Reason for revert:
Caused failures in DrMemory:

UNADDRESSABLE ACCESS of freed memory: writing 0x031c0278-0x031c0279 1 byte(s)
# 0 ppapi_tests.dll!`anonymous namespace'::InstanceSO::~InstanceSO             [ppapi\tests\test_instance_deprecated.cc:48]
# 1 ppapi_tests.dll!`anonymous namespace'::InstanceSO::`scalar deleting destructor'
# 2 ppapi_tests.dll!pp::deprecated::`anonymous namespace'::Deallocate          [ppapi\cpp\dev\scriptable_object_deprecated.cc:126]
# 3 ppapi_proxy.dll!ppapi::CallWhileUnlocked<>                                 [ppapi\shared_impl\proxy_lock.h:123]
# 4 ppapi_proxy.dll!ppapi::proxy::PluginVarTracker::DidDeleteInstance          [ppapi\proxy\plugin_var_tracker.cc:281]
# 5 ppapi_proxy.dll!ppapi::proxy::PPP_Instance_Proxy::OnPluginMsgDidDestroy    [ppapi\proxy\ppp_instance_proxy.cc:194]
# 6 ppapi_proxy.dll!PpapiMsg_PPPInstance_DidDestroy::Dispatch<>                [ppapi\proxy\ppapi_messages.h:670]
# 7 ppapi_proxy.dll!ppapi::proxy::PPP_Instance_Proxy::OnMessageReceived        [ppapi\proxy\ppp_instance_proxy.cc:143]
# 8 ppapi_proxy.dll!ppapi::proxy::Dispatcher::OnMessageReceived                [ppapi\proxy\dispatcher.cc:69]
# 9 ppapi_proxy.dll!ppapi::proxy::PluginDispatcher::OnMessageReceived          [ppapi\proxy\plugin_dispatcher.cc:238]
#10 ipc.dll!IPC::ChannelProxy::Context::OnDispatchMessage                      [ipc\ipc_channel_proxy.cc:273]
#11 ipc.dll!base::internal::Invoker<>::Run                                     [base\bind_internal.h:1253]
#12 base.dll!base::debug::TaskAnnotator::RunTask                               [base\debug\task_annotator.cc:62]
#13 base.dll!base::MessageLoop::RunTask                                        [base\message_loop\message_loop.cc:436]
#14 base.dll!base::MessageLoop::DeferOrRunPendingTask                          [base\message_loop\message_loop.cc:445]
#15 base.dll!base::MessageLoop::DoWork                                         [base\message_loop\message_loop.cc:552]
#16 base.dll!base::MessagePumpDefault::Run                                     [base\message_loop\message_pump_default.cc:32]
#17 base.dll!base::MessageLoop::RunHandler                                     [base\message_loop\message_loop.cc:408]
#18 content.dll!content::PpapiPluginMain                                       [content\ppapi_plugin\ppapi_plugin_main.cc:141]
#19 content.dll!content::RunNamedProcessTypeMain                               [content\app\content_main_runner.cc:415]
#20 content.dll!content::ContentMainRunnerImpl::Run                            [content\app\content_main_runner.cc:764]
#21 content.dll!content::ContentMain                                           [content\app\content_main.cc:19]
#22 content::LaunchTests                                                       [content\public\test\test_launcher.cc:475]
#23 main                                                                       [content\test\content_test_launcher.cc:123]


First appeared in http://build.chromium.org/p/chromium.memory.fyi/builders/Windows%20Content%20Browser%20%28DrMemory%29/builds/631/steps/memory%20test%3A%20content_browsertests/logs/stdio.

Original issue's description:
> Minor changes to allow Pepper InstancePrivate tests to pass with gin
> 
> This includes some minor changes which allow tests to when NPObject is replaced
> by gin in pepper:
> -Add shared library exports for use of PepperTryCatch and ScopedPPVarArray in
> tests.
> -Add gin as a dependency to content_unittests for use in host_var_tracker_unittest
> -Change TestInstanceDeprecated so that it doesn't execute a script from the
> ScriptableObject upon destruction. The reason for this is that the garbage
> collector is manually run from the destructor of the plugin Instance object.
> This results in destruction of the ScriptableObject and then javascript is
> re-entered via ExecuteScript. This should never happen outside tests because
> the garbage collector won't be run synchronously. Instead of running
> ExecuteScript, which just set a variable in the Instance object to verify
> that the ScriptableObject was correctly destroyed.
> 
> BUG=351636
> 
> Committed: https://chromium.googlesource.com/chromium/src/+/92c3074f4b4417924115f880657f1ec15da0e0ba

TBR=dmichael@chromium.org,raymes@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=351636, 407372
Committed: https://crrev.com/c399366bf15d052f8efdbee029de69e8e12b8a9a
Cr-Commit-Position: refs/heads/master@{#291780}

[Jeffrey Yasskin, 2014-08-25 22:46:42]

Created Revert of Minor changes to allow Pepper InstancePrivate tests to pass
with gin

[dmichael (off chromium), 2014-08-25 22:58:09]

lgtm

[Jeffrey Yasskin, 2014-08-25 23:08:08]

The CQ bit was checked by jyasskin@chromium.org

[commit-bot: I haz the power, 2014-08-25 23:11:26]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jyasskin@chromium.org/502143003/1

[commit-bot: I haz the power, 2014-08-25 23:13:42]

Committed patchset #1 (1) as 8dc4e794b65db30db5942953b5a9d2f7e0b48133

[commit-bot: I haz the power, 2014-09-10 02:38:15]

Patchset 1 (id:??) landed as
https://crrev.com/c399366bf15d052f8efdbee029de69e8e12b8a9a
Cr-Commit-Position: refs/heads/master@{#291780}