Prioritize tiles near the viewport in out-of-viewport layers

cc/resources/picture_layer_tiling_unittest.cc

Index: cc/resources/picture_layer_tiling_unittest.cc
diff --git a/cc/resources/picture_layer_tiling_unittest.cc b/cc/resources/picture_layer_tiling_unittest.cc
index 91043e67b48006e13d72f42781c97fd55828fcdb..c57b9fc5dbf898c5dd00992a04059181f38d1421 100644
--- a/cc/resources/picture_layer_tiling_unittest.cc
+++ b/cc/resources/picture_layer_tiling_unittest.cc
@@ -358,5 +358,16 @@ TEST(PictureLayerTilingTest, ExpandRectOutOfBounds) {
   EXPECT_TRUE(out.IsEmpty());
 }
 
+TEST(PictureLayerTilingTest, ExpandRectBySizeBoundedBy) {
+  gfx::Rect in(0, 0, 100, 100);
+  gfx::Rect bounds(0, 0, 1000, 1000);
+  gfx::Rect out = PictureLayerTiling::ExpandRectBySizeBoundedBy(
+      in, 512, 512, bounds);
+  EXPECT_EQ(out.x(), 0);
+  EXPECT_EQ(out.y(), 0);
+  EXPECT_EQ(out.width(), 612);
+  EXPECT_EQ(out.height(), 612);
+}
+
 }  // namespace
 }  // namespace cc