Exposes more mutation functions to MotionEventGeneric

ui/events/gesture_detection/motion_event_generic_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/events/event_constants.h"
 #include "ui/events/gesture_detection/motion_event_generic.h"
 #include "ui/events/test/motion_event_test_utils.h"
 
 namespace ui {
@@ skipping 112 matching lines @@
   base::TimeTicks event_time = base::TimeTicks::Now();
   PointerProperties pointer;
   pointer.id = 0;
   MotionEventGeneric event0(MotionEvent::ACTION_DOWN, event_time, pointer);
   EXPECT_EQ(0, event0.FindPointerIndexOfId(0));
   EXPECT_EQ(-1, event0.FindPointerIndexOfId(1));
   EXPECT_EQ(-1, event0.FindPointerIndexOfId(-1));
 
   MotionEventGeneric event1(event0);
   pointer.id = 7;
-  event1.PushPointer(pointer);
+  EXPECT_EQ(1u, event1.PushPointer(pointer));
   EXPECT_EQ(0, event1.FindPointerIndexOfId(0));
   EXPECT_EQ(1, event1.FindPointerIndexOfId(7));
   EXPECT_EQ(-1, event1.FindPointerIndexOfId(6));
   EXPECT_EQ(-1, event1.FindPointerIndexOfId(1));
 
   MotionEventGeneric event2(event1);
   pointer.id = 3;
-  event2.PushPointer(pointer);
+  EXPECT_EQ(2u, event2.PushPointer(pointer));
   EXPECT_EQ(0, event2.FindPointerIndexOfId(0));
   EXPECT_EQ(1, event2.FindPointerIndexOfId(7));
   EXPECT_EQ(2, event2.FindPointerIndexOfId(3));
   EXPECT_EQ(-1, event2.FindPointerIndexOfId(1));
   EXPECT_EQ(-1, event2.FindPointerIndexOfId(2));
 }
 
+TEST(MotionEventGenericTest, RemovePointerAt) {
+  base::TimeTicks event_time = base::TimeTicks::Now();
+  PointerProperties pointer;
+  pointer.id = 0;
+  MotionEventGeneric event(MotionEvent::ACTION_DOWN, event_time, pointer);
+
+  pointer.id = 7;
+  EXPECT_EQ(1u, event.PushPointer(pointer));
+  EXPECT_EQ(2u, event.GetPointerCount());
+
+  // Remove from the end.
+  event.RemovePointerAt(1);
+  EXPECT_EQ(1u, event.GetPointerCount());
+  EXPECT_EQ(-1, event.FindPointerIndexOfId(7));
+  EXPECT_EQ(0, event.FindPointerIndexOfId(0));
+
+  EXPECT_EQ(1u, event.PushPointer(pointer));
+  EXPECT_EQ(2u, event.GetPointerCount());
+
+  // Remove from the beginning.
+  event.RemovePointerAt(0);
+  EXPECT_EQ(1u, event.GetPointerCount());
+  EXPECT_EQ(0, event.FindPointerIndexOfId(7));
+  EXPECT_EQ(-1, event.FindPointerIndexOfId(0));
+}
+
 TEST(MotionEventGenericTest, ToString) {
   base::TimeTicks event_time = base::TimeTicks::Now();
   base::TimeTicks historical_event_time0 =
       event_time - base::TimeDelta::FromMilliseconds(10);
   base::TimeTicks historical_event_time1 =
       event_time - base::TimeDelta::FromMilliseconds(5);
 
   PointerProperties pointer0(1, 2, 3);
   pointer0.id = 7;
   pointer0.pressure = 10;
@@ skipping 28 matching lines @@
   ASSERT_EQ(2U, event.GetHistorySize());
   ASSERT_EQ(2U, event.GetPointerCount());
 
   // Do a basic smoke exercise of event stringification to ensure things don't
   // explode in the process.
   std::string event_string = test::ToString(event);
   EXPECT_FALSE(event_string.empty());
 }
 
 }  // namespace ui