Create InputThread to manage inputflinger threads

InputReader and InputDispatcher both manage their own threads. To help
manage input processing threads that have elevated priority/nice values,
we create the InputThread class.

Creating an InputThread starts the thread immediately, and loops the
loop function until the InputThread object is destructed.

Bug: 130819454
Test: atest inputflinger_tests
Test: Touch input works on crosshatch
Change-Id: I2cb56250fc62300e195c5b2474d32c2db3fa4711
diff --git a/services/inputflinger/reader/InputReader.cpp b/services/inputflinger/reader/InputReader.cpp
index 05f0db1..2023c6e 100644
--- a/services/inputflinger/reader/InputReader.cpp
+++ b/services/inputflinger/reader/InputReader.cpp
@@ -49,25 +49,6 @@
 
 namespace android {
 
-// --- InputReader::InputReaderThread ---
-
-/* Thread that reads raw events from the event hub and processes them, endlessly. */
-class InputReader::InputReaderThread : public Thread {
-public:
-    explicit InputReaderThread(InputReader* reader)
-          : Thread(/* canCallJava */ true), mReader(reader) {}
-
-    ~InputReaderThread() {}
-
-private:
-    InputReader* mReader;
-
-    bool threadLoop() override {
-        mReader->loopOnce();
-        return true;
-    }
-};
-
 // --- InputReader ---
 
 InputReader::InputReader(std::shared_ptr<EventHubInterface> eventHub,
@@ -83,7 +64,6 @@
         mNextTimeout(LLONG_MAX),
         mConfigurationChangesToRefresh(0) {
     mQueuedListener = new QueuedInputListener(listener);
-    mThread = new InputReaderThread(this);
 
     { // acquire lock
         AutoMutex _l(mLock);
@@ -100,25 +80,21 @@
 }
 
 status_t InputReader::start() {
-    if (mThread->isRunning()) {
+    if (mThread) {
         return ALREADY_EXISTS;
     }
-    return mThread->run("InputReader", PRIORITY_URGENT_DISPLAY);
+    mThread = std::make_unique<InputThread>(
+            "InputReader", [this]() { loopOnce(); }, [this]() { mEventHub->wake(); });
+    return OK;
 }
 
 status_t InputReader::stop() {
-    if (!mThread->isRunning()) {
-        return OK;
-    }
-    if (gettid() == mThread->getTid()) {
-        ALOGE("InputReader can only be stopped from outside of the InputReaderThread!");
+    if (mThread && mThread->isCallingThread()) {
+        ALOGE("InputReader cannot be stopped from its own thread!");
         return INVALID_OPERATION;
     }
-    // Directly calling requestExitAndWait() causes the thread to not exit
-    // if mEventHub is waiting for a long timeout.
-    mThread->requestExit();
-    mEventHub->wake();
-    return mThread->requestExitAndWait();
+    mThread.reset();
+    return OK;
 }
 
 void InputReader::loopOnce() {