gfx: Make conversions from Size to SizeF be explicit.

cc/trees/layer_tree_impl.cc

 // Copyright 2011 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 "cc/trees/layer_tree_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 
@@ skipping 144 matching lines @@
   set_needs_update_draw_properties();
   return root_layer_.Pass();
 }
 
 static void UpdateClipTreeForBoundsDeltaOnLayer(LayerImpl* layer,
                                                 ClipTree* clip_tree) {
   if (layer && layer->masks_to_bounds()) {
     ClipNode* clip_node = clip_tree->Node(layer->clip_tree_index());
     if (clip_node) {
       DCHECK_EQ(layer->id(), clip_node->owner_id);
-      gfx::Size bounds = layer->bounds();
+      gfx::SizeF bounds = gfx::SizeF(layer->bounds());
       if (clip_node->data.clip.size() != bounds) {
         clip_node->data.clip.set_size(bounds);
         clip_tree->set_needs_update(true);
       }
     }
   }
 }
 
 void LayerTreeImpl::UpdatePropertyTreesForBoundsDelta() {
   DCHECK(IsActiveTree());
@@ skipping 536 matching lines @@
   // the unoccluded_screen_space_region_ is not valid anymore.
   DCHECK(!needs_update_draw_properties_);
   return unoccluded_screen_space_region_;
 }
 
 gfx::SizeF LayerTreeImpl::ScrollableSize() const {
   LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
                                      ? OuterViewportScrollLayer()
                                      : InnerViewportScrollLayer();
   if (!root_scroll_layer || root_scroll_layer->children().empty())
-    return gfx::Size();
+    return gfx::SizeF();
 
   gfx::SizeF content_size =
       root_scroll_layer->children()[0]->BoundsForScrolling();
   gfx::SizeF viewport_size =
       root_scroll_layer->scroll_clip_layer()->BoundsForScrolling();
 
   content_size.SetToMax(viewport_size);
   return content_size;
 }
 
@@ skipping 975 matching lines @@
                                                    const gfx::BoxF& box,
                                                    gfx::BoxF* bounds) const {
   *bounds = gfx::BoxF();
   return layer_tree_host_impl_->animation_host()
              ? layer_tree_host_impl_->animation_host()
                    ->TransformAnimationBoundsForBox(layer->id(), box, bounds)
              : true;
 }
 
 }  // namespace cc