Move DeleteDragDetails to destructor in PipWindowResizer.

Bug: b/127224879
Test: drag-move an Android PIP window - no crash upon finishing drag.
Change-Id: I3d455f3545ea1a7bfba4c9ec6f6b51d3b218078d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1498744
Commit-Queue: Eliot Courtney <edcourtney@chromium.org>
Reviewed-by: Yuichiro Hanada <yhanada@chromium.org>
Cr-Commit-Position: refs/heads/master@{#637606}

ash/wm/pip/pip_window_resizer.cc

@@ -96,7 +96,11 @@ PipWindowResizer::PipWindowResizer(wm::WindowState* window_state)
   }
 }
 
-PipWindowResizer::~PipWindowResizer() {}
+PipWindowResizer::~PipWindowResizer() {
+  // Drag details should be deleted upon destruction of the resizer.
+  if (window_state())
+    window_state()->DeleteDragDetails();
+}
 
 // TODO(edcourtney): Implement swipe-to-dismiss on fling.
 void PipWindowResizer::Drag(const gfx::Point& location_in_parent,
@@ -190,7 +194,7 @@ void PipWindowResizer::CompleteDrag() {
   }
 
   window_state()->OnCompleteDrag(last_location_in_screen_);
-  window_state()->DeleteDragDetails();
+
   window_state()->ClearRestoreBounds();
   window_state()->set_bounds_changed_by_user(moved_or_resized_);
 

ash/wm/pip/pip_window_resizer_unittest.cc

@@ -592,6 +592,23 @@ TEST_P(PipWindowResizerTest, PipFreeResizeAreaUmaMetrics) {
   histograms().ExpectTotalCount(kAshPipFreeResizeFinishAreaHistogramName, 1);
 }
 
+TEST_P(PipWindowResizerTest, DragDetailsAreDestroyed) {
+  PreparePipWindow(gfx::Rect(200, 200, 100, 100));
+  wm::WindowState* window_state = wm::GetWindowState(window());
+
+  {
+    std::unique_ptr<PipWindowResizer> resizer(CreateResizerForTest(HTCAPTION));
+    ASSERT_TRUE(resizer.get());
+
+    resizer->Drag(CalculateDragPoint(*resizer, 0, 10), 0);
+    EXPECT_NE(nullptr, window_state->drag_details());
+
+    resizer->CompleteDrag();
+    EXPECT_NE(nullptr, window_state->drag_details());
+  }
+  EXPECT_EQ(nullptr, window_state->drag_details());
+}
+
 // TODO: UpdateDisplay() doesn't support different layouts of multiple displays.
 // We should add some way to try multiple layouts.
 INSTANTIATE_TEST_SUITE_P(