ui/gfx: Convert CreateCanvas to use gfx::Size.

ui/gfx/compositor/layer_unittest.cc

Index: ui/gfx/compositor/layer_unittest.cc
diff --git a/ui/gfx/compositor/layer_unittest.cc b/ui/gfx/compositor/layer_unittest.cc
index 3f7d886c7daa259949363fe6b45ef8d501637d99..1839cbe836b9f1f8928ab2efe86fac27da5d5dee 100644
--- a/ui/gfx/compositor/layer_unittest.cc
+++ b/ui/gfx/compositor/layer_unittest.cc
@@ -86,9 +86,7 @@ class LayerWithRealCompositorTest : public testing::Test {
   }
 
   gfx::Canvas* CreateCanvasForLayer(const Layer* layer) {
-    return gfx::Canvas::CreateCanvas(layer->bounds().width(),
-                                     layer->bounds().height(),
-                                     false);
+    return gfx::Canvas::CreateCanvas(layer->bounds().size(), false);
   }
 
   void DrawTree(Layer* root) {
@@ -267,9 +265,7 @@ class LayerWithDelegateTest : public testing::Test {
   }
 
   gfx::Canvas* CreateCanvasForLayer(const Layer* layer) {
-    return gfx::Canvas::CreateCanvas(layer->bounds().width(),
-                                     layer->bounds().height(),
-                                     false);
+    return gfx::Canvas::CreateCanvas(layer->bounds().size(), false);
   }
 
   void DrawTree(Layer* root) {