Added more robust tracking and cancelation of events.

This change fixes several issues where events would be dropped in the
input dispatch pipeline in such a way that the dispatcher could not
accurately track the state of the input device.

Given more robust tracking, we can now also provide robust cancelation
of input events in cases where an application might otherwise become
out of sync with the event stream due to ANR, app switch, policy decisions,
or forced focus transitions.

Pruned some of the input dispatcher log output.

Moved the responsibility for calling intercept*BeforeQueueing into
the input dispatcher instead of the input reader and added support for
early interception of injected events for events coming from trusted
sources.  This enables behaviors like injection of media keys while
the screen is off, haptic feedback of injected virtual keys, so injected
events become more "first class" in a way.

Change-Id: Iec6ff1dd21e5f3c7feb80ea4feb5382bd090dbd9
diff --git a/include/ui/Input.h b/include/ui/Input.h
index ee40b85..66061fd 100644
--- a/include/ui/Input.h
+++ b/include/ui/Input.h
@@ -71,6 +71,8 @@
 /*
  * Flags that flow alongside events in the input dispatch system to help with certain
  * policy decisions such as waking from device sleep.
+ *
+ * These flags are also defined in frameworks/base/core/java/android/view/WindowManagerPolicy.java.
  */
 enum {
     /* These flags originate in RawEvents and are generally set in the key map.
@@ -102,6 +104,11 @@
     // Indicates that the screen was dim when the event was received and the event
     // should brighten the device.
     POLICY_FLAG_BRIGHT_HERE = 0x20000000,
+
+    // Indicates that the event should be dispatched to applications.
+    // The input event should still be sent to the InputDispatcher so that it can see all
+    // input events received include those that it will not deliver.
+    POLICY_FLAG_PASS_TO_USER = 0x40000000,
 };
 
 /*