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

cc/trees/layer_tree_host_pixeltest_readback.cc

Index: cc/trees/layer_tree_host_pixeltest_readback.cc
diff --git a/cc/trees/layer_tree_host_pixeltest_readback.cc b/cc/trees/layer_tree_host_pixeltest_readback.cc
index 6af0bb2f8d029f888e40c04dea7e55a0c21cd6f1..b65feccda04a480a9e3fe407a6548b122c287c06 100644
--- a/cc/trees/layer_tree_host_pixeltest_readback.cc
+++ b/cc/trees/layer_tree_host_pixeltest_readback.cc
@@ -391,7 +391,7 @@ TEST_P(LayerTreeHostReadbackPixelTest, ReadbackNonRootLayerOutsideViewport) {
       CreateSolidColorLayer(gfx::Rect(200, 200), SK_ColorGREEN);
   // Only the top left quarter of the layer is inside the viewport, so the
   // blue layer is entirely outside.
-  green->SetPosition(gfx::Point(100, 100));
+  green->SetPosition(gfx::PointF(100.f, 100.f));
   background->AddChild(green);
 
   scoped_refptr<SolidColorLayer> blue =
@@ -497,7 +497,7 @@ TEST_P(LayerTreeHostReadbackDeviceScalePixelTest, ReadbackSubrect) {
 
   scoped_refptr<FakePictureLayer> blue =
       FakePictureLayer::Create(layer_settings(), &blue_client_);
-  blue->SetPosition(gfx::Point(50, 50));
+  blue->SetPosition(gfx::PointF(50.f, 50.f));
   blue->SetBounds(gfx::Size(25, 25));
   blue->SetIsDrawable(true);
   green->AddChild(blue);
@@ -518,14 +518,14 @@ TEST_P(LayerTreeHostReadbackDeviceScalePixelTest, ReadbackNonRootLayerSubrect) {
 
   scoped_refptr<FakePictureLayer> green =
       FakePictureLayer::Create(layer_settings(), &green_client_);
-  green->SetPosition(gfx::Point(10, 20));
+  green->SetPosition(gfx::PointF(10.f, 20.f));
   green->SetBounds(gfx::Size(90, 80));
   green->SetIsDrawable(true);
   background->AddChild(green);
 
   scoped_refptr<FakePictureLayer> blue =
       FakePictureLayer::Create(layer_settings(), &blue_client_);
-  blue->SetPosition(gfx::Point(50, 50));
+  blue->SetPosition(gfx::PointF(50.f, 50.f));
   blue->SetBounds(gfx::Size(25, 25));
   blue->SetIsDrawable(true);
   green->AddChild(blue);