exo: Fix CreateLinuxFence test.

components/exo/display_unittest.cc

Index: components/exo/display_unittest.cc
diff --git a/components/exo/display_unittest.cc b/components/exo/display_unittest.cc
index 675e21f3f4536042583f1e434e7ff23c38d60e30..62217c7d3580064b1098ea096a76e048a4c29ac0 100644
--- a/components/exo/display_unittest.cc
+++ b/components/exo/display_unittest.cc
@@ -12,6 +12,11 @@
 #include "components/exo/test/exo_test_base.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_LINUX)
+#include "third_party/libsync/include/sw_sync.h"
+#include "ui/gfx/gpu_fence.h"
+#endif
+
 #if defined(USE_OZONE)
 #include "ui/ozone/public/native_pixmap.h"
 #include "ui/ozone/public/ozone_platform.h"
@@ -86,39 +91,47 @@ TEST_F(DisplayTest, DISABLED_CreateLinuxDMABufBuffer) {
   EXPECT_FALSE(buffer2);
 }
 
+// TODO(dcastagna): Add YV12 unittest once we can allocate the buffer
+// via Ozone. crbug.com/618516
+#endif  // defined(USE_OZONE)
+
+#if defined(OS_LINUX)
 TEST_F(DisplayTest, CreateLinuxFence) {
-  int sockets_unscoped[2];
+  std::unique_ptr<Display> display(new Display);
 
-  ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_STREAM, 0, fds));
+  // Skip test if sw sync device doesn't exist.
+  if (!base::PathExists(base::FilePath(FILE_PATH_LITERAL("/dev/sw_sync"))))
+    return;
 
-  // Emulate the behaviour of a fence FD (returns POLLIN when signaled) using
-  // a socket pair.
-  Base::ScopedFD socket_waitee(sockets_unscoped[0]);
+  // Initial position for timeline is 0.
+  base::ScopedFD timeline_fd(sw_sync_timeline_create());
+  ASSERT_TRUE(timeline_fd.is_valid());
+
+  int sync_point = 1;
+  // Create a fence for |sync_point|.
+  base::ScopedFD fence_fd(
+      sw_sync_fence_create(timeline_fd.get(), "cr-test-fence", sync_point));
 
   std::unique_ptr<gfx::GpuFence> fence1 =
-      display->CreateLinuxFence(sockets_unscoped[1]);
+      display->CreateLinuxFence(std::move(fence_fd));
   ASSERT_TRUE(fence1);
-  close(sockets_unscoped[1]);
 
   // The fence must be unsignaled when we start.
-  EXPECT_FALSE(fence1->Wait(TimeDelta::FromMilliseconds(50)));
+  EXPECT_FALSE(fence1->IsSignaled());
 
-  // Unblock the fence, and make sure this signals success.
-  uint32_t dummy = 1;
-  ASSERT_EQ(sizeof(dummy), UnixDomainSocket::SendMsg(socket_waitee, &dummy,
-                                                     sizeof(dummy), nullptr));
+  // Increment timeline to 1 to signal fence.
+  int rv = sw_sync_timeline_inc(timeline_fd.get(), 1);
+  EXPECT_EQ(0, rv);
 
-  EXPECT_TRUE(fence1->Wait(TimeDelta::FromMilliseconds(50)));
+  EXPECT_TRUE(fence1->Wait(base::TimeDelta::FromMilliseconds(50)));
 
+  base::ScopedFD invalid_fd;
   // Check that invalid file descriptors are rejected.
-  std::unique_ptr<gfx::GpuFence> fence2 = display->CreateLinuxFence(-1);
+  std::unique_ptr<gfx::GpuFence> fence2 =
+      display->CreateLinuxFence(std::move(invalid_fd));
   EXPECT_FALSE(fence2);
 }
-
-// TODO(dcastagna): Add YV12 unittest once we can allocate the buffer
-// via Ozone. crbug.com/618516
-
-#endif
+#endif  // defined(OS_LINUX)
 
 TEST_F(DisplayTest, CreateShellSurface) {
   std::unique_ptr<Display> display(new Display);