Properly cleans up state when mouse capture changes.

ui/aura/window_unittest.cc

Index: ui/aura/window_unittest.cc
diff --git a/ui/aura/window_unittest.cc b/ui/aura/window_unittest.cc
index f16fd54285e747b1b909ae3291e8a78af1850f57..d8124464cb8911baf057499741469529847cc892 100644
--- a/ui/aura/window_unittest.cc
+++ b/ui/aura/window_unittest.cc
@@ -371,7 +371,7 @@ TEST_F(WindowTest, StackChildAbove) {
   EXPECT_EQ(child3.layer(), parent.layer()->children()[2]);
 }
 
-// Various destruction assertions.
+// Various capture assertions.
 TEST_F(WindowTest, CaptureTests) {
   aura::RootWindow* root_window = aura::RootWindow::GetInstance();
   CaptureWindowDelegateImpl delegate;
@@ -415,6 +415,35 @@ TEST_F(WindowTest, CaptureTests) {
   EXPECT_EQ(NULL, root_window->capture_window());
 }
 
+// Changes capture while capture is already ongoing.
+TEST_F(WindowTest, ChangeCaptureWhileMouseDown) {
+  CaptureWindowDelegateImpl delegate;
+  scoped_ptr<Window> window(CreateTestWindowWithDelegate(
+      &delegate, 0, gfx::Rect(0, 0, 20, 20), NULL));
+  CaptureWindowDelegateImpl delegate2;
+  scoped_ptr<Window> w2(CreateTestWindowWithDelegate(
+      &delegate2, 0, gfx::Rect(20, 20, 20, 20), NULL));
+  EXPECT_FALSE(window->HasCapture());
+
+  // Do a capture.
+  window->SetCapture();
+  delegate.set_mouse_event_count(0);
+  EXPECT_TRUE(window->HasCapture());
+  EXPECT_EQ(0, delegate.capture_lost_count());
+  EventGenerator generator(gfx::Point(50, 50));
+  generator.PressLeftButton();
+  EXPECT_EQ(1, delegate.mouse_event_count());
+  delegate.set_mouse_event_count(0);
+
+  // Reset the capture.
+  window->ReleaseCapture();
+  w2->SetCapture();
+  delegate2.set_mouse_event_count(0);
+  generator.MoveMouseTo(gfx::Point(40, 40));
+  EXPECT_EQ(0, delegate.mouse_event_count());
+  EXPECT_EQ(2, delegate2.mouse_event_count());
+}
+
 // Verifies capture is reset when a window is destroyed.
 TEST_F(WindowTest, ReleaseCaptureOnDestroy) {
   RootWindow* root_window = RootWindow::GetInstance();