Address comments

lib/ui/window/pointer_data_packet_converter_unittests.cc

@@ -11,8 +11,6 @@
 namespace flutter {
 namespace testing {
 
-static constexpr int64_t kImplicitViewId = 0;
-
 void CreateSimulatedPointerData(PointerData& data,  // NOLINT
                                 PointerData::Change change,
                                 int64_t device,
@@ -131,7 +129,7 @@ void CreateSimulatedTrackpadGestureData(PointerData& data,  // NOLINT
   data.pan_delta_y = 0.0;
   data.scale = scale;
   data.rotation = rotation;
-  data.view_id = kImplicitViewId;
+  data.view_id = 0;
 }
 
 void UnpackPointerPacket(std::vector<PointerData>& output,  // NOLINT

shell/platform/android/io/flutter/embedding/android/AndroidTouchProcessor.java

@@ -260,7 +260,7 @@ private void addPointerForIndex(
     }
     // TODO(dkwingsmt): Use the correct source view ID once Android supports
     // multiple views.
-    // https://github.com/flutter/flutter/issues/138167
+    // https://github.com/flutter/flutter/issues/134405
     final int viewId = IMPLICIT_VIEW_ID;
     final int pointerId = event.getPointerId(pointerIndex);
 

shell/platform/embedder/embedder.h

@@ -266,6 +266,15 @@ typedef enum {
 
 typedef struct _FlutterEngine* FLUTTER_API_SYMBOL(FlutterEngine);
 
+/// Identifier for views.
+///
+/// The responsibility for generating view IDs lies with the embedding. The
+/// engine does not assume any specifics about the generation algorithm,
+/// including whether it utilizes the entire range of int64_t or permits the
+/// use of zero or negative IDs. The only requirement is that at any given
+/// moment, no two views share the same ID.
+typedef int64_t FlutterViewId;
+
 typedef struct {
   /// horizontal scale factor
   double scaleX;
@@ -962,7 +971,7 @@ typedef struct {
   /// The rotation of the pan/zoom in radians, where 0.0 is the initial angle.
   double rotation;
   /// The identifier of the view that received the pointer event.
-  int64_t view_id;
+  FlutterViewId view_id;
 } FlutterPointerEvent;
 
 typedef enum {

shell/platform/windows/flutter_windows_view.cc

@@ -20,13 +20,6 @@ namespace {
 // for a window resize operation to complete.
 constexpr std::chrono::milliseconds kWindowResizeTimeout{100};
 
-// TODO(dkwingsmt): Use the correct view ID for pointer events once the Windows
-// embedder supports multiple views.
-// https://github.com/flutter/flutter/issues/138179
-int64_t _viewIdForPointerEvent() {
-  return flutter::kFlutterImplicitViewId;
-}
-
 /// Returns true if the surface will be updated as part of the resize process.
 ///
 /// This is called on window resize to determine if the platform thread needs
@@ -372,7 +365,6 @@ void FlutterWindowsView::SendPointerMove(double x,
   FlutterPointerEvent event = {};
   event.x = x;
   event.y = y;
-  event.view_id = _viewIdForPointerEvent();
 
   SetEventPhaseFromCursorButtonState(&event, state);
   SendPointerEventWithData(event, state);
@@ -384,7 +376,6 @@ void FlutterWindowsView::SendPointerDown(double x,
   FlutterPointerEvent event = {};
   event.x = x;
   event.y = y;
-  event.view_id = _viewIdForPointerEvent();
 
   SetEventPhaseFromCursorButtonState(&event, state);
   SendPointerEventWithData(event, state);
@@ -398,7 +389,6 @@ void FlutterWindowsView::SendPointerUp(double x,
   FlutterPointerEvent event = {};
   event.x = x;
   event.y = y;
-  event.view_id = _viewIdForPointerEvent();
 
   SetEventPhaseFromCursorButtonState(&event, state);
   SendPointerEventWithData(event, state);
@@ -414,7 +404,6 @@ void FlutterWindowsView::SendPointerLeave(double x,
   event.x = x;
   event.y = y;
   event.phase = FlutterPointerPhase::kRemove;
-  event.view_id = _viewIdForPointerEvent();
   SendPointerEventWithData(event, state);
 }
 
@@ -429,7 +418,6 @@ void FlutterWindowsView::SendPointerPanZoomStart(int32_t device_id,
   event.x = x;
   event.y = y;
   event.phase = FlutterPointerPhase::kPanZoomStart;
-  event.view_id = _viewIdForPointerEvent();
   SendPointerEventWithData(event, state);
 }
 
@@ -448,7 +436,6 @@ void FlutterWindowsView::SendPointerPanZoomUpdate(int32_t device_id,
   event.scale = scale;
   event.rotation = rotation;
   event.phase = FlutterPointerPhase::kPanZoomUpdate;
-  event.view_id = _viewIdForPointerEvent();
   SendPointerEventWithData(event, state);
 }
 
@@ -459,7 +446,6 @@ void FlutterWindowsView::SendPointerPanZoomEnd(int32_t device_id) {
   event.x = state->pan_zoom_start_x;
   event.y = state->pan_zoom_start_y;
   event.phase = FlutterPointerPhase::kPanZoomEnd;
-  event.view_id = _viewIdForPointerEvent();
   SendPointerEventWithData(event, state);
 }
 
@@ -517,7 +503,6 @@ void FlutterWindowsView::SendScroll(double x,
   event.signal_kind = FlutterPointerSignalKind::kFlutterPointerSignalKindScroll;
   event.scroll_delta_x = delta_x * scroll_offset_multiplier;
   event.scroll_delta_y = delta_y * scroll_offset_multiplier;
-  event.view_id = _viewIdForPointerEvent();
   SetEventPhaseFromCursorButtonState(&event, state);
   SendPointerEventWithData(event, state);
 }
@@ -533,7 +518,6 @@ void FlutterWindowsView::SendScrollInertiaCancel(int32_t device_id,
   event.y = y;
   event.signal_kind =
       FlutterPointerSignalKind::kFlutterPointerSignalKindScrollInertiaCancel;
-  event.view_id = _viewIdForPointerEvent();
   SetEventPhaseFromCursorButtonState(&event, state);
   SendPointerEventWithData(event, state);
 }
@@ -550,7 +534,6 @@ void FlutterWindowsView::SendPointerEventWithData(
     event.x = event_data.x;
     event.y = event_data.y;
     event.buttons = 0;
-    event.view_id = _viewIdForPointerEvent();
     SendPointerEventWithData(event, state);
   }
 
@@ -565,7 +548,10 @@ void FlutterWindowsView::SendPointerEventWithData(
   event.device_kind = state->device_kind;
   event.device = state->pointer_id;
   event.buttons = state->buttons;
-  event.view_id = _viewIdForPointerEvent();
+  // TODO(dkwingsmt): Use the correct view ID for pointer events once the
+  // Windows embedder supports multiple views.
+  // https://github.com/flutter/flutter/issues/138179
+  event.view_id = flutter::kFlutterImplicitViewId;
 
   // Set metadata that's always the same regardless of the event.
   event.struct_size = sizeof(event);