diff -r 000000000000 -r 6474c204b198 browser/devtools/shadereditor/test/browser_webgl-actor-test-14.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/shadereditor/test/browser_webgl-actor-test-14.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,46 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests that the rendering is updated when a uniform variable is
+ * changed in one shader of a page with multiple WebGL contexts.
+ */
+
+function ifWebGLSupported() {
+  let [target, debuggee, front] = yield initBackend(MULTIPLE_CONTEXTS_URL);
+  front.setup({ reload: true });
+
+  let [firstProgramActor, secondProgramActor] = yield getPrograms(front, 2);
+
+  let firstFragmentShader = yield firstProgramActor.getFragmentShader();
+  let secondFragmentShader = yield secondProgramActor.getFragmentShader();
+
+  let oldFragSource = yield firstFragmentShader.getText();
+  let newFragSource = oldFragSource.replace("vec4(uColor", "vec4(0.25, 0.25, 0.25");
+  let status = yield firstFragmentShader.compile(newFragSource);
+  ok(!status,
+    "The first new fragment shader source was compiled without errors.");
+
+  yield waitForFrame(debuggee);
+  yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 64, g: 64, b: 64, a: 255 }, true, "#canvas1");
+  yield ensurePixelIs(debuggee, { x: 127, y: 127 }, { r: 64, g: 64, b: 64, a: 255 }, true, "#canvas1");
+  yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 0, g: 255, b: 255, a: 255 }, true, "#canvas2");
+  yield ensurePixelIs(debuggee, { x: 127, y: 127 }, { r: 0, g: 255, b: 255, a: 255 }, true, "#canvas2");
+  ok(true, "The first fragment shader was changed.");
+
+  let oldFragSource = yield secondFragmentShader.getText();
+  let newFragSource = oldFragSource.replace("vec4(uColor", "vec4(0.75, 0.75, 0.75");
+  let status = yield secondFragmentShader.compile(newFragSource);
+  ok(!status,
+    "The second new fragment shader source was compiled without errors.");
+
+  yield waitForFrame(debuggee);
+  yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 64, g: 64, b: 64, a: 255 }, true, "#canvas1");
+  yield ensurePixelIs(debuggee, { x: 127, y: 127 }, { r: 64, g: 64, b: 64, a: 255 }, true, "#canvas1");
+  yield ensurePixelIs(debuggee, { x: 0, y: 0 }, { r: 191, g: 191, b: 191, a: 255 }, true, "#canvas2");
+  yield ensurePixelIs(debuggee, { x: 127, y: 127 }, { r: 191, g: 191, b: 191, a: 255 }, true, "#canvas2");
+  ok(true, "The second fragment shader was changed.");
+
+  yield removeTab(target.tab);
+  finish();
+}