Bug 468024 - reftest.js : optimize |outputs| assignment(s); (Av2) Check for no tests case, Whitespace cleanups; r=dbaron

layout/tools/reftest/reftest.js

@@ -196,6 +196,10 @@ function StartTests()
         ReadTopManifest(window.arguments[0]);
         BuildUseCounts();
         gTotalTests = gURLs.length;
+
+        if (!gTotalTests)
+            throw "No tests to run";
+
         gURICanvases = {};
         StartCurrentTest();
     } catch (ex) {
@@ -872,6 +876,7 @@ function DocumentLoaded()
             // what is expected on this platform (PASS, FAIL, or RANDOM)
             var expected = gURLs[0].expected;
 
+            // Not 'const ...' because of 'EXPECTED_*' value dependency.
             var outputs = {};
             const randomMsg = "(EXPECTED RANDOM)";
             outputs[EXPECTED_PASS] = {