Use PooledLambda.obtainMessage() when possible

As its JavaDoc says, in most of cases PooledLambda.obtainMessage() is
a better choice than PooledLambda.obtainRunnable().

If PooledLambda.obtainRunnable() is really necessary, let's make sure
to call recycleOnUse() whenever possible.

Test: presubmit
Change-Id: I3dbe500f49c0df187f2ffefd11c71836696dfd4e

core/java/android/app/ActivityThread.java

@@ -1541,7 +1541,7 @@ public final class ActivityThread extends ClientTransactionHandler {
 
         public void scheduleTrimMemory(int level) {
             final Runnable r = PooledLambda.obtainRunnable(ActivityThread::handleTrimMemory,
-                    ActivityThread.this, level);
+                    ActivityThread.this, level).recycleOnUse();
             // Schedule trimming memory after drawing the frame to minimize jank-risk.
             Choreographer choreographer = Choreographer.getMainThreadInstance();
             if (choreographer != null) {

core/java/android/app/UiAutomation.java

@@ -1197,10 +1197,9 @@ public final class UiAutomation {
                     }
                     if (listener != null) {
                         // Calling out only without a lock held.
-                        mLocalCallbackHandler.post(PooledLambda.obtainRunnable(
+                        mLocalCallbackHandler.sendMessage(PooledLambda.obtainMessage(
                                 OnAccessibilityEventListener::onAccessibilityEvent,
-                                listener, AccessibilityEvent.obtain(event))
-                                .recycleOnUse());
+                                listener, AccessibilityEvent.obtain(event)));
                     }
                 }