Let InputReader set mouse cursor's display.

InputReader was already responsible to bind device/event and display. It
makes sense to further extend it to control the display where mouse
cursor is shown.

Bug: 146385350
Test: Mouse cursor shows up at expected display.
Test: atest inputflinger_tests
Change-Id: Ie7a9546550b70c8834462b06de929472196fe713
diff --git a/services/inputflinger/reader/mapper/CursorInputMapper.cpp b/services/inputflinger/reader/mapper/CursorInputMapper.cpp
index f69138e..69a75ba 100644
--- a/services/inputflinger/reader/mapper/CursorInputMapper.cpp
+++ b/services/inputflinger/reader/mapper/CursorInputMapper.cpp
@@ -189,12 +189,32 @@
 
         // Update the PointerController if viewports changed.
         if (mParameters.mode == Parameters::MODE_POINTER) {
-            getPolicy()->obtainPointerController(getDeviceId());
+            updatePointerControllerDisplayViewport(*config);
         }
         bumpGeneration();
     }
 }
 
+void CursorInputMapper::updatePointerControllerDisplayViewport(
+        const InputReaderConfiguration& config) {
+    std::optional<DisplayViewport> viewport =
+            config.getDisplayViewportById(config.defaultPointerDisplayId);
+    if (!viewport) {
+        ALOGW("Can't find the designated viewport with ID %" PRId32 " to update cursor input "
+              "mapper. Fall back to default display",
+              config.defaultPointerDisplayId);
+        viewport = config.getDisplayViewportById(ADISPLAY_ID_DEFAULT);
+    }
+
+    if (!viewport) {
+        ALOGE("Still can't find a viable viewport to update cursor input mapper. Skip setting it to"
+              " PointerController.");
+        return;
+    }
+
+    mPointerController->setDisplayViewport(*viewport);
+}
+
 void CursorInputMapper::configureParameters() {
     mParameters.mode = Parameters::MODE_POINTER;
     String8 cursorModeString;