gfx: Make conversions from gfx::Point to PointF explicit.

ash/wm/gestures/overview_gesture_handler_unittest.cc

 // Copyright 2013 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 "ash/root_window_controller.h"
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
 #include "ash/wm/overview/window_selector_controller.h"
 #include "ui/aura/test/test_window_delegate.h"
 #include "ui/aura/test/test_windows.h"
@@ skipping 71 matching lines @@
 // Tests a swipe up with three fingers without releasing followed by a swipe
 // down by a lesser amount which should still be enough to exit.
 TEST_F(OverviewGestureHandlerTest, SwipeUpDownWithoutReleasing) {
   gfx::Rect bounds(0, 0, 400, 400);
   aura::Window* root_window = Shell::GetPrimaryRootWindow();
   scoped_ptr<aura::Window> window1(CreateWindow(bounds));
   scoped_ptr<aura::Window> window2(CreateWindow(bounds));
   ui::test::EventGenerator generator(root_window, root_window);
   base::TimeDelta timestamp = base::TimeDelta::FromInternalValue(
       base::TimeTicks::Now().ToInternalValue());
-  gfx::Point start;
+  gfx::PointF start;
   int num_fingers = 3;
   base::TimeDelta step_delay(base::TimeDelta::FromMilliseconds(5));
   ui::ScrollEvent fling_cancel(ui::ET_SCROLL_FLING_CANCEL,
                                start,
                                timestamp,
                                0,
                                0, 0,
                                0, 0,
                                num_fingers);
   generator.Dispatch(&fling_cancel);
@@ skipping 31 matching lines @@
                               start,
                               timestamp,
                               0,
                               0, 10,
                               0, 10,
                               num_fingers);
   generator.Dispatch(&fling_start);
 }
 
 }  // namespace ash