diff -r 000000000000 -r 6474c204b198 browser/devtools/shadereditor/test/browser_webgl-actor-test-10.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/shadereditor/test/browser_webgl-actor-test-10.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,44 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests if the WebGL context is correctly instrumented every time the
+ * target navigates.
+ */
+
+function ifWebGLSupported() {
+  let [target, debuggee, front] = yield initBackend(SIMPLE_CANVAS_URL);
+
+  front.setup({ reload: true });
+  yield testHighlighting((yield once(front, "program-linked")));
+  ok(true, "Canvas was correctly instrumented on the first navigation.");
+
+  reload(target);
+  yield testHighlighting((yield once(front, "program-linked")));
+  ok(true, "Canvas was correctly instrumented on the second navigation.");
+
+  reload(target);
+  yield testHighlighting((yield once(front, "program-linked")));
+  ok(true, "Canvas was correctly instrumented on the third navigation.");
+
+  yield removeTab(target.tab);
+  finish();
+
+  function testHighlighting(programActor) {
+    return Task.spawn(function() {
+      yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 255, g: 0, b: 0, a: 255 }, true);
+      yield ensurePixelIs(debuggee, { x: 511, y: 511 }, { r: 0, g: 255, b: 0, a: 255 }, true);
+      ok(true, "The corner pixel colors are correct before highlighting.");
+
+      yield programActor.highlight([0, 1, 0, 1]);
+      yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 0, g: 0, b: 0, a: 255 }, true);
+      yield ensurePixelIs(debuggee, { x: 511, y: 511 }, { r: 0, g: 255, b: 0, a: 255 }, true);
+      ok(true, "The corner pixel colors are correct after highlighting.");
+
+      yield programActor.unhighlight();
+      yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 255, g: 0, b: 0, a: 255 }, true);
+      yield ensurePixelIs(debuggee, { x: 511, y: 511 }, { r: 0, g: 255, b: 0, a: 255 }, true);
+      ok(true, "The corner pixel colors are correct after unhighlighting.");
+    });
+  }
+}