Allow batching samples onto the pending motion event. (DO NOT MERGE)

This enlarges the window of opportunity for batching to
encompass time spent for the window to become ready (while it is
busy processing the last event).

Change-Id: I8870cc3081d27a4de659fb4e375f888fe966460b
diff --git a/services/input/InputDispatcher.cpp b/services/input/InputDispatcher.cpp
index 7ac2f13..5e6f241 100644
--- a/services/input/InputDispatcher.cpp
+++ b/services/input/InputDispatcher.cpp
@@ -2403,6 +2403,34 @@
                 return; // done!
             }
 
+            // BATCHING ONTO PENDING EVENT CASE
+            //
+            // Try to append a move sample to the currently pending event, if there is one.
+            // We can do this as long as we are still waiting to find the targets for the
+            // event.  Once the targets are locked-in we can only do streaming.
+            if (mPendingEvent
+                    && (!mPendingEvent->dispatchInProgress || !mCurrentInputTargetsValid)
+                    && mPendingEvent->type == EventEntry::TYPE_MOTION) {
+                MotionEntry* motionEntry = static_cast<MotionEntry*>(mPendingEvent);
+                if (motionEntry->deviceId == deviceId && motionEntry->source == source) {
+                    if (motionEntry->action != action
+                            || motionEntry->pointerCount != pointerCount
+                            || motionEntry->isInjected()) {
+                        // Pending event is not compatible for appending new samples.  Stop here.
+                        goto NoBatchingOrStreaming;
+                    }
+
+                    // The pending motion event is a move and is compatible for appending.
+                    // Do the batching magic.
+                    mAllocator.appendMotionSample(motionEntry, eventTime, pointerCoords);
+#if DEBUG_BATCHING
+                    LOGD("Appended motion sample onto batch for the pending motion event.");
+#endif
+                    mLock.unlock();
+                    return; // done!
+                }
+            }
+
             // STREAMING CASE
             //
             // There is no pending motion event (of any kind) for this device in the inbound queue.