Make it possible to have 1 PpapiGlobals per thread. Update unit tests.

ppapi/proxy/ppapi_proxy_test.cc

Index: ppapi/proxy/ppapi_proxy_test.cc
diff --git a/ppapi/proxy/ppapi_proxy_test.cc b/ppapi/proxy/ppapi_proxy_test.cc
index 8ab8c36153455d7b13b7c150b330e21f0b23048e..a322811795ba9aa5c75dbaf8d9f03c98a7f2061f 100644
--- a/ppapi/proxy/ppapi_proxy_test.cc
+++ b/ppapi/proxy/ppapi_proxy_test.cc
@@ -166,6 +166,7 @@ void PluginProxyTestHarness::SetUpHarnessWithChannel(
     base::WaitableEvent* shutdown_event,
     bool is_client) {
   // These must be first since the dispatcher set-up uses them.
+  PpapiGlobals::SetPpapiGlobalsForTest(GetGlobals());
   resource_tracker().DidCreateInstance(pp_instance());
   plugin_delegate_mock_.Init(ipc_message_loop, shutdown_event);
 
@@ -272,7 +273,10 @@ void HostProxyTestHarness::SetUpHarnessWithChannel(
     base::MessageLoopProxy* ipc_message_loop,
     base::WaitableEvent* shutdown_event,
     bool is_client) {
+  // These must be first since the dispatcher set-up uses them.
+  PpapiGlobals::SetPpapiGlobalsForTest(GetGlobals());
   delegate_mock_.Init(ipc_message_loop, shutdown_event);
+
   host_dispatcher_.reset(new HostDispatcher(
       base::Process::Current().handle(),
       pp_module(),
@@ -345,7 +349,6 @@ void TwoWayTest::SetUp() {
 
   IPC::ChannelHandle handle;
   handle.name = "TwoWayTestChannel";
-
   base::WaitableEvent remote_harness_set_up(true, false);
   plugin_thread_.message_loop_proxy()->PostTask(
       FROM_HERE,