Use shared_ptr for InjectionState

This removes the need for manual ref-counting for InjectionState.

Bug: 210460522
Test: atest inputflinger_tests
Change-Id: I7d959e761afaba86b8e733e0e73c39196ef6d8bc
diff --git a/services/inputflinger/dispatcher/InjectionState.cpp b/services/inputflinger/dispatcher/InjectionState.cpp
index 053594b..f693dcf 100644
--- a/services/inputflinger/dispatcher/InjectionState.cpp
+++ b/services/inputflinger/dispatcher/InjectionState.cpp
@@ -20,22 +20,10 @@
 
 namespace android::inputdispatcher {
 
-InjectionState::InjectionState(const std::optional<gui::Uid>& targetUid)
-      : refCount(1),
-        targetUid(targetUid),
+InjectionState::InjectionState(const std::optional<gui::Uid>& targetUid, bool isAsync)
+      : targetUid(targetUid),
+        injectionIsAsync(isAsync),
         injectionResult(android::os::InputEventInjectionResult::PENDING),
-        injectionIsAsync(false),
         pendingForegroundDispatches(0) {}
 
-InjectionState::~InjectionState() {}
-
-void InjectionState::release() {
-    refCount -= 1;
-    if (refCount == 0) {
-        delete this;
-    } else {
-        ALOG_ASSERT(refCount > 0);
-    }
-}
-
 } // namespace android::inputdispatcher