Remove redundant isSplit assignments

Now that touch is always split (except for mouse events), we can
also simplify the assignment of isSplit variable and make it const.

Eventually, we can consider changing the touchpad code so that we can
completely remove the non-split code handling from dispatcher and
simplify this even further, because touchpad scroll should always go to
the location of the cursor.

Bug: 239934827
Test: TEST=inputflinger_tests; m $TEST && $ANDROID_HOST_OUT/nativetest64/$TEST/$TEST
Flag: EXEMPT refactor
Change-Id: Ib753f798fd77d5d74434b9cbb02f17cd07f5906b

Author: vishniakou

services/inputflinger/dispatcher/InputDispatcher.cpp

@@ -2412,7 +2412,7 @@ InputDispatcher::findTouchedWindowTargetsLocked(nsecs_t currentTime, const Motio
         tempTouchState = *oldState;
     }
 
-    bool isSplit = shouldSplitTouch(entry.source);
+    const bool isSplit = shouldSplitTouch(entry.source);
 
     const bool isHoverAction = (maskedAction == AMOTION_EVENT_ACTION_HOVER_MOVE ||
                                 maskedAction == AMOTION_EVENT_ACTION_HOVER_ENTER ||
@@ -2425,11 +2425,6 @@ InputDispatcher::findTouchedWindowTargetsLocked(nsecs_t currentTime, const Motio
     const bool newGesture = isDown || maskedAction == AMOTION_EVENT_ACTION_SCROLL ||
             maskedAction == AMOTION_EVENT_ACTION_HOVER_ENTER ||
             maskedAction == AMOTION_EVENT_ACTION_HOVER_MOVE;
-    const bool isFromMouse = isFromSource(entry.source, AINPUT_SOURCE_MOUSE);
-
-    if (newGesture) {
-        isSplit = false;
-    }
 
     if (isDown && tempTouchState.hasHoveringPointers(entry.deviceId)) {
         // Compatibility behaviour: ACTION_DOWN causes HOVER_EXIT to get generated.
@@ -2472,8 +2467,6 @@ InputDispatcher::findTouchedWindowTargetsLocked(nsecs_t currentTime, const Motio
             return injectionError(InputEventInjectionResult::TARGET_MISMATCH);
         }
 
-        isSplit = !isFromMouse;
-
         std::vector<sp<WindowInfoHandle>> newTouchedWindows =
                 mWindowInfos.findTouchedSpyWindowsAt(displayId, x, y, isStylus, entry.deviceId,
                                                      mTouchStatesByDisplay);
@@ -2647,7 +2640,6 @@ InputDispatcher::findTouchedWindowTargetsLocked(nsecs_t currentTime, const Motio
                                              targets);
 
                 // Make a slippery entrance into the new window.
-                isSplit = !isFromMouse;
 
                 ftl::Flags<InputTarget::Flags> targetFlags;
                 if (canReceiveForegroundTouches(*newTouchedWindowHandle->getInfo())) {