gl_tests: Use zero size gl surface for offscreen rendering

gpu/command_buffer/client/mapped_memory_unittest.cc

Index: gpu/command_buffer/client/mapped_memory_unittest.cc
diff --git a/gpu/command_buffer/client/mapped_memory_unittest.cc b/gpu/command_buffer/client/mapped_memory_unittest.cc
index 9d5badac656358816e2bcb4755418141ef1852d2..be9b0b01f17903aea5100ea58ab04d217cf6b1c5 100644
--- a/gpu/command_buffer/client/mapped_memory_unittest.cc
+++ b/gpu/command_buffer/client/mapped_memory_unittest.cc
@@ -74,7 +74,9 @@ class MappedMemoryTestBase : public testing::Test {
 #if defined(OS_MACOSX)
   base::mac::ScopedNSAutoreleasePool autorelease_pool_;
 #endif
+#if !defined(USE_OZONE)
   base::MessageLoop message_loop_;
+#endif
   scoped_ptr<AsyncAPIMock> api_mock_;
   scoped_ptr<TransferBufferManagerInterface> transfer_buffer_manager_;
   scoped_ptr<CommandBufferService> command_buffer_;