auto merge of #5231 : dmarcos/servo/issue4784, r=jdm

...ce

1 files changed, 10 insertions, 0 deletions

diff --git a/components/script/dom/htmlcanvaselement.rs b/components/script/dom/htmlcanvaselement.rs
index 9c3c11d5dbc..e4fc68565a3 100644
--- a/components/script/dom/htmlcanvaselement.rs
+++ b/components/script/dom/htmlcanvaselement.rs
@@ -91,12 +91,22 @@ impl LayoutHTMLCanvasElementHelpers for LayoutJS<HTMLCanvasElement> {
 
 pub trait HTMLCanvasElementHelpers {
     fn get_size(&self) -> Size2D<i32>;
+    fn get_2d_context(self) -> Temporary<CanvasRenderingContext2D>;
+    fn is_valid(self) -> bool;
 }
 
 impl<'a> HTMLCanvasElementHelpers for JSRef<'a, HTMLCanvasElement> {
     fn get_size(&self) -> Size2D<i32> {
         Size2D(self.Width() as i32, self.Height() as i32)
     }
+
+    fn get_2d_context(self) -> Temporary<CanvasRenderingContext2D> {
+        self.GetContext(String::from_str("2d")).unwrap()
+    }
+
+    fn is_valid(self) -> bool {
+        self.height.get() != 0 && self.width.get() != 0
+    }
 }
 
 impl<'a> HTMLCanvasElementMethods for JSRef<'a, HTMLCanvasElement> {