Fix Firefox tests, add it to travis.yml

1. Don't use PointerEvents for tests in Firefox, see #6539.  This makes
all tests but one pass.

2. Run built files against FirefhoxHeadless. This means we run unminified
on Chrome and minified on Firefox.  This helps keep the build time down
by not running everything twice on both browsers, but will still catch
Firefox-specific bugs that we can then run locally.

.travis.yml

@@ -4,6 +4,7 @@ node_js:
 sudo: false
 addons:
   chrome: stable
+  firefox: latest
 before_script:
   - export DISPLAY=:99.0
   - sh -e /etc/init.d/xvfb start
@@ -19,7 +20,7 @@ script:
 
   - echo 'test webgl-stub' && echo -en 'travis_fold:start:script.test\\r'
   - npm run build
-  - npm run test -- --browsers ChromeCI --webgl-stub --failTaskOnError --suppressPassed
+  - npm run test -- --browsers FirefoxHeadless --webgl-stub --failTaskOnError --suppressPassed
   - echo -en 'travis_fold:end:script.test\\r'
 
   - echo 'makeZipFile' && echo -en 'travis_fold:start:script.makeZipFile\\r'
@@ -38,7 +39,7 @@ script:
   - echo -en 'travis_fold:end:script.deploy\\r'
 
   - echo 'test webgl-stub release' && echo -en 'travis_fold:start:script test.release\\r'
-  - npm run test -- --browsers ChromeCI --failTaskOnError --webgl-stub --release --suppressPassed
+  - npm run test -- --browsers FirefoxHeadless --failTaskOnError --webgl-stub --release --suppressPassed
   - echo -en 'travis_fold:end:script test.release\\r'
 
   - echo 'test node' && echo -en 'travis_fold:start:script test.node\\r'

Specs/Core/ScreenSpaceEventHandlerSpec.js

@@ -20,7 +20,7 @@ defineSuite([
         DomEventSimulator) {
     'use strict';
 
-    var usePointerEvents = FeatureDetection.supportsPointerEvents();
+    var usePointerEvents;
     var element;
     var handler;
 
@@ -63,6 +63,16 @@ defineSuite([
         event.preventDefault();
     }
 
+    beforeAll(function(){
+        usePointerEvents = FeatureDetection.supportsPointerEvents();
+
+        //See https://github.com/AnalyticalGraphicsInc/cesium/issues/6539
+        if (FeatureDetection.isFirefox()) {
+            usePointerEvents = false;
+            spyOn(FeatureDetection, 'supportsPointerEvents').and.returnValue(false);
+        }
+    });
+
     beforeEach(function() {
         // ignore events that bubble up to the document.
         // this prevents triggering the browser's "middle click to scroll" behavior

Specs/Scene/CameraEventAggregatorSpec.js

@@ -18,12 +18,19 @@ defineSuite([
         DomEventSimulator) {
     'use strict';
 
-    var usePointerEvents = FeatureDetection.supportsPointerEvents();
+    var usePointerEvents;
     var canvas;
     var handler;
     var handler2;
 
     beforeAll(function() {
+        usePointerEvents = FeatureDetection.supportsPointerEvents();
+
+        //See https://github.com/AnalyticalGraphicsInc/cesium/issues/6539
+        if (FeatureDetection.isFirefox()) {
+            usePointerEvents = false;
+            spyOn(FeatureDetection, 'supportsPointerEvents').and.returnValue(false);
+        }
         canvas = createCanvas(1024, 768);
     });
 

Specs/Scene/ScreenSpaceCameraControllerSpec.js

@@ -44,7 +44,7 @@ defineSuite([
         DomEventSimulator) {
     'use strict';
 
-    var usePointerEvents = FeatureDetection.supportsPointerEvents();
+    var usePointerEvents;
     var scene;
     var canvas;
     var camera;
@@ -80,6 +80,13 @@ defineSuite([
         };
     }
     beforeAll(function() {
+        usePointerEvents = FeatureDetection.supportsPointerEvents();
+
+        //See https://github.com/AnalyticalGraphicsInc/cesium/issues/6539
+        if (FeatureDetection.isFirefox()) {
+            usePointerEvents = false;
+            spyOn(FeatureDetection, 'supportsPointerEvents').and.returnValue(false);
+        }
         canvas = createCanvas(1024, 768);
     });