Divide InputDispatcher into several files.

This CL does:
1) Isolate implementation details of InputDispatcher from outside and
only expose necessary header files;
2) Move implementation details into android::inputdispatcher namespace;
3) Make input dispatcher a static library for inputflinger to link
against;
4) Add InputDispatcherFactory.{h,cpp} to isolate implementation details
in InputDispatcher.h from InputManager.

Bug: 140139676
Test: Touches on touchscreen can be dispatched to right windows.
Change-Id: Ib61c16fd41f3f76f538a3de9b54f31ac304e03a5
diff --git a/services/inputflinger/dispatcher/InjectionState.cpp b/services/inputflinger/dispatcher/InjectionState.cpp
new file mode 100644
index 0000000..b2d0a26
--- /dev/null
+++ b/services/inputflinger/dispatcher/InjectionState.cpp
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "InjectionState.h"
+
+#include <log/log.h>
+
+namespace android::inputdispatcher {
+
+InjectionState::InjectionState(int32_t injectorPid, int32_t injectorUid)
+      : refCount(1),
+        injectorPid(injectorPid),
+        injectorUid(injectorUid),
+        injectionResult(INPUT_EVENT_INJECTION_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