Revert of PPAPI: Make tests that disable the proxy lock re-enable it

ppapi/shared_impl/var_tracker_unittest.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "testing/gtest/include/gtest/gtest.h"
 
 #include "base/compiler_specific.h"
 #include "ppapi/shared_impl/proxy_lock.h"
 #include "ppapi/shared_impl/var.h"
 #include "ppapi/shared_impl/var_tracker.h"
@@ skipping 24 matching lines @@
 
 }  // namespace
 
 class VarTrackerTest : public testing::Test {
  public:
   VarTrackerTest() {}
 
   // Test implementation.
   virtual void SetUp() override {
     ASSERT_EQ(0, mock_var_alive_count);
+    ProxyLock::EnableLockingOnThreadForTest();
   }
   virtual void TearDown() override {}
 
   VarTracker& var_tracker() { return *globals_.GetVarTracker(); }
 
  private:
   TestGlobals globals_;
 };
 
 // Test that ResetVarID is called when the last PP_Var ref was deleted but the
@@ skipping 87 matching lines @@
   another_var = NULL;
   EXPECT_TRUE(var_tracker().GetVar(pp_var));
   EXPECT_EQ(1, mock_var_alive_count);
 
   // Releasing plugin reference.
   EXPECT_TRUE(var_tracker().ReleaseVar(pp_var));
   EXPECT_EQ(0, mock_var_alive_count);
 }
 
 }  // namespace ppapi