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

ppapi/shared_impl/proxy_lock.cc

Index: ppapi/shared_impl/proxy_lock.cc
diff --git a/ppapi/shared_impl/proxy_lock.cc b/ppapi/shared_impl/proxy_lock.cc
index 3d8493052a56a168e0ad5cf7ef65741d98b54154..bf4db65f8b490a53fb185e4871fa8d62d92ec24e 100644
--- a/ppapi/shared_impl/proxy_lock.cc
+++ b/ppapi/shared_impl/proxy_lock.cc
@@ -5,31 +5,22 @@
 #include "ppapi/shared_impl/proxy_lock.h"
 
 #include "base/synchronization/lock.h"
+#include "ppapi/shared_impl/ppapi_globals.h"
 
 namespace ppapi {
 
-base::Lock* ProxyLock::lock_ = NULL;
-
 // static
 void ProxyLock::Acquire() {
-  if (lock_)
-    lock_->Acquire();
+  base::Lock* lock(PpapiGlobals::Get()->GetProxyLock());
+  if (lock)
+    lock->Acquire();
 }
 
 // static
 void ProxyLock::Release() {
-  if (lock_)
-    lock_->Release();
-}
-
-// static
-void ProxyLock::Set(base::Lock* lock) {
-  lock_ = lock;
-}
-
-// static
-void ProxyLock::Reset() {
-  Set(NULL);
+  base::Lock* lock(PpapiGlobals::Get()->GetProxyLock());
+  if (lock)
+    lock->Release();
 }
 
 }  // namespace ppapi