libhwui: AnimatedImageThread - UAF

Fix branch subject to UAF.

Bug: 186468053
Test: atest android.graphics.drawable.cts.AnimatedImageDrawableTest
    (w/ UAF detection enabled in libutils Thread)
Change-Id: Idb45f5ef41436920d0ce00f609fa25fb8fdccddf

libs/hwui/hwui/AnimatedImageThread.cpp

@@ -22,13 +22,16 @@ namespace android {
 namespace uirenderer {
 
 AnimatedImageThread& AnimatedImageThread::getInstance() {
-    static AnimatedImageThread* sInstance = new AnimatedImageThread();
-    return *sInstance;
+    [[clang::no_destroy]] static sp<AnimatedImageThread> sInstance = []() {
+        sp<AnimatedImageThread> thread = sp<AnimatedImageThread>::make();
+        thread->start("AnimatedImageThread");
+        return thread;
+    }();
+    return *sInstance.get();
 }
 
 AnimatedImageThread::AnimatedImageThread() {
     setpriority(PRIO_PROCESS, 0, PRIORITY_NORMAL + PRIORITY_MORE_FAVORABLE);
-    start("AnimatedImageThread");
 }
 
 std::future<AnimatedImageDrawable::Snapshot> AnimatedImageThread::decodeNextFrame(

libs/hwui/hwui/AnimatedImageThread.h

@@ -37,6 +37,7 @@ public:
     std::future<AnimatedImageDrawable::Snapshot> reset(const sk_sp<AnimatedImageDrawable>&);
 
 private:
+    friend sp<AnimatedImageThread>;
     AnimatedImageThread();
 };