Move some definitions into anonymous namespaces

To prevent ODR violations, move some of the definitions into anonymous
namespaces.
Specifically, this solves the issue of multiple definitions for
FakeWindowHandle, which was triggering the leak sanitizer check when
'sanitize: address' was set to true.

Bug: 284203306
Test: m inputflinger_tests && $ANDROID_HOST_OUT/nativetest64/inputflinger_tests/inputflinger_tests
Change-Id: I106b2b547cf465df15e317a9b7478dcc77467a46
diff --git a/services/inputflinger/tests/InputDispatcher_test.cpp b/services/inputflinger/tests/InputDispatcher_test.cpp
index e6b73af..779d389 100644
--- a/services/inputflinger/tests/InputDispatcher_test.cpp
+++ b/services/inputflinger/tests/InputDispatcher_test.cpp
@@ -846,6 +846,8 @@
     mFakePolicy->assertNotifySwitchWasCalled(args);
 }
 
+namespace {
+
 // --- InputDispatcherTest SetInputWindowTest ---
 static constexpr std::chrono::duration INJECT_EVENT_TIMEOUT = 500ms;
 // Default input dispatching timeout if there is no focused application or paused window
@@ -1592,6 +1594,8 @@
     return NotifyPointerCaptureChangedArgs(/*id=*/0, systemTime(SYSTEM_TIME_MONOTONIC), request);
 }
 
+} // namespace
+
 /**
  * When a window unexpectedly disposes of its input channel, policy should be notified about the
  * broken channel.