[palmoni5]

Problem

WindowManager.setBounds in the 0.5.x-compatible legacy API always read the window's current bounds through nativeapi (a synchronous FFI call) before applying new ones. It did this even when the caller passed a full Rect, so none of the values it read were used. Apps that restore or move the window with a full Rect pay for that extra native round trip on every call.

Change

• The current bounds are now read only when bounds is null and position and/or size give a partial update.
• The behavior is otherwise the same: a full Rect still takes precedence over position/size, animate still tries animateBounds first and falls back to a plain set, and an empty request is still a no-op.
• Adds a @visibleForTesting debugBindWindow hook so the bridge can be tested against a Dart fake window. The hunk is identical to the one in fix(legacy): report show/hide and fix restore tracking #602, fix(legacy): keep the event bridge compiling when nativeapi adds events #604 and fix(legacy): show taskbar progress and badge on this app's window #605, so those PRs merge with this one without conflicts.

Tests

New test/legacy_set_bounds_test.dart, with its own fake nativeapi.Window that counts bounds reads. It checks that:

• a full Rect is applied with no bounds read;
• position-only and size-only updates still read the omitted values;
• a full Rect wins over position/size;
• animate: true falls back to a plain set;
• an empty request does nothing.

dart format, flutter analyze (package and example) and flutter test all pass locally.