Sends ACTION_CANCEL before the very first touch exploration HOVER event.

This resets the InputDispatcher state in case the user had a pointer
down (and kept it down) before enabling TalkBack or while booting up
the device before TalkBack has started up.

Fix: 364408887
Test: atest TouchExplorerTest
Test: touch and hold on the screen;
      start TalkBack with a shortcut or adb shell;
      lift your finger off the screen;
      touch the screen again, and observe that touch exploration
      functions properly.
Flag: com.android.server.accessibility.reset_input_dispatcher_before_first_touch_exploration
Change-Id: I1c2bdb7b3d32cd124257e60e8c91c073c3040f50
diff --git a/services/accessibility/accessibility.aconfig b/services/accessibility/accessibility.aconfig
index 8e2e0ad..3f604ca 100644
--- a/services/accessibility/accessibility.aconfig
+++ b/services/accessibility/accessibility.aconfig
@@ -209,6 +209,16 @@
 }
 
 flag {
+    name: "reset_input_dispatcher_before_first_touch_exploration"
+    namespace: "accessibility"
+    description: "Resets InputDispatcher state by sending ACTION_CANCEL before the first TouchExploration hover events"
+    bug: "364408887"
+    metadata {
+        purpose: PURPOSE_BUGFIX
+    }
+}
+
+flag {
     name: "scan_packages_without_lock"
     namespace: "accessibility"
     description: "Scans packages for accessibility service/activity info without holding the A11yMS lock"
@@ -221,6 +231,7 @@
     description: "Sends accessibility events in TouchExplorer#onAccessibilityEvent based on internal state to keep it consistent. This reduces test flakiness."
     bug: "295575684"
 }
+
 flag {
     name: "send_hover_events_based_on_event_stream"
     namespace: "accessibility"