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

cc/test/layer_tree_pixel_test.cc

Index: cc/test/layer_tree_pixel_test.cc
diff --git a/cc/test/layer_tree_pixel_test.cc b/cc/test/layer_tree_pixel_test.cc
index 50ec17a5b1cfe3dabc0bb409e5c03d8e6dd1d190..a8e3c1cf716c36be0c3891fa5aee9efebf8ab916 100644
--- a/cc/test/layer_tree_pixel_test.cc
+++ b/cc/test/layer_tree_pixel_test.cc
@@ -122,7 +122,7 @@ scoped_refptr<SolidColorLayer> LayerTreePixelTest::CreateSolidColorLayer(
       SolidColorLayer::Create(layer_settings());
   layer->SetIsDrawable(true);
   layer->SetBounds(rect.size());
-  layer->SetPosition(rect.origin());
+  layer->SetPosition(gfx::PointF(rect.origin()));
   layer->SetBackgroundColor(color);
   return layer;
 }
@@ -180,7 +180,7 @@ scoped_refptr<TextureLayer> LayerTreePixelTest::CreateTextureLayer(
       TextureLayer::CreateForMailbox(layer_settings(), NULL);
   layer->SetIsDrawable(true);
   layer->SetBounds(rect.size());
-  layer->SetPosition(rect.origin());
+  layer->SetPosition(gfx::PointF(rect.origin()));
 
   TextureMailbox texture_mailbox;
   scoped_ptr<SingleReleaseCallback> release_callback;