Revert "[ozone/x11] Enabled user input monitor unit tests."

This reverts commit 30a60064.

Reason for revert: Suspicious about causing test failures.
https://ci.chromium.org/p/chromium/builders/ci/linux-lacros-tester-rel/4433

Original change's description:
> [ozone/x11] Enabled user input monitor unit tests.
>
> This CL adds Ozone platform initialisation to the user input monitor tests
> so they can now work with Ozone enabled.
>
> Bug: 1109112
> Change-Id: I31f9dabf2da9eed85cd05fe27017899b0247f4bc
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2521144
> Commit-Queue: Alexander Dunaev <adunaev@igalia.com>
> Reviewed-by: Scott Violet <sky@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#826638}

TBR=sky@chromium.org,adunaev@igalia.com

Change-Id: Ic8cd3da17dd5d2de01981aa9a8f33b6a55621c43
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1109112
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2531810Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826688}

media/base/user_input_monitor_unittest.cc

@@ -19,35 +19,19 @@
 
 #if defined(USE_OZONE)
 #include "ui/base/ui_base_features.h"  // nogncheck
-#include "ui/ozone/public/ozone_platform.h"  // nogncheck
 #endif
 
 namespace media {
 
-namespace {
-
-class UserInputMonitorTest : public testing::Test {
- protected:
-  // testing::Test.
-  void SetUp() override {
+TEST(UserInputMonitorTest, CreatePlatformSpecific) {
 #if defined(USE_OZONE)
-    if (features::IsUsingOzonePlatform()) {
-      if (std::strcmp(ui::OzonePlatform::GetPlatformName(), "drm") == 0) {
-        // OzonePlatformDrm::InitializeUI hangs in tests.
-        GTEST_SKIP();
-      }
-      // Initialise Ozone in single process mode, as all tests do.
-      ui::OzonePlatform::InitParams params;
-      params.single_process = true;
-      ui::OzonePlatform::InitializeForUI(params);
-    }
+  // TODO(crbug.com/1109112): enable those tests for Ozone.
+  // Here, the only issue why they don't work is that the Ozone platform is not
+  // initialised.
+  if (features::IsUsingOzonePlatform())
+    return;
 #endif
-  }
-};
 
-}  // namespace
-
-TEST_F(UserInputMonitorTest, CreatePlatformSpecific) {
 #if defined(OS_LINUX) || defined(OS_CHROMEOS)
   base::test::TaskEnvironment task_environment(
       base::test::TaskEnvironment::MainThreadType::IO);
@@ -69,7 +53,15 @@ TEST_F(UserInputMonitorTest, CreatePlatformSpecific) {
   base::RunLoop().RunUntilIdle();
 }
 
-TEST_F(UserInputMonitorTest, CreatePlatformSpecificWithMapping) {
+TEST(UserInputMonitorTest, CreatePlatformSpecificWithMapping) {
+#if defined(USE_OZONE)
+  // TODO(crbug.com/1109112): enable those tests for Ozone.
+  // Here, the only issue why they don't work is that the Ozone platform is not
+  // initialised.
+  if (features::IsUsingOzonePlatform())
+    return;
+#endif
+
 #if defined(OS_LINUX) || defined(OS_CHROMEOS)
   base::test::TaskEnvironment task_environment(
       base::test::TaskEnvironment::MainThreadType::IO);
@@ -98,7 +90,7 @@ TEST_F(UserInputMonitorTest, CreatePlatformSpecificWithMapping) {
   EXPECT_EQ(0u, ReadKeyPressMonitorCount(readonly_mapping));
 }
 
-TEST_F(UserInputMonitorTest, ReadWriteKeyPressMonitorCount) {
+TEST(UserInputMonitorTest, ReadWriteKeyPressMonitorCount) {
   std::unique_ptr<base::MappedReadOnlyRegion> shmem =
       std::make_unique<base::MappedReadOnlyRegion>(
           base::ReadOnlySharedMemoryRegion::Create(sizeof(uint32_t)));