Bug 1130287 - Expose isB2G in SpecialPowers. r=sicking

Some mochitests needs to behave differently when ran on B2G Desktop.
Currently, this is implemented using user agent string detection,
mostly relying on "Mobile" being present and "Android" being absent.
This is only true on B2G Desktop when ran on Try because the mozconfig
defined FXOS_SIMULATOR and that, per bug 1115935, this substring is only
added in this case, but not if just MOZ_B2G is defined. A better
approach is to expose 'isB2G' in SpecialPowers for this kind of
detection.

testing/marionette/jar.mn

@@ -23,7 +23,7 @@ marionette.jar:
 % content specialpowers %content/
   content/specialpowers.js (../specialpowers/content/specialpowers.js)
   content/SpecialPowersObserver.js (../specialpowers/components/SpecialPowersObserver.js)
-  content/specialpowersAPI.js (../specialpowers/content/specialpowersAPI.js)
+* content/specialpowersAPI.js (../specialpowers/content/specialpowersAPI.js)
   content/SpecialPowersObserverAPI.js (../specialpowers/content/SpecialPowersObserverAPI.js)
   content/ChromePowers.js (../mochitest/tests/SimpleTest/ChromePowers.js)
   content/MozillaLogger.js (../specialpowers/content/MozillaLogger.js)

testing/mochitest/jar.mn

@@ -26,7 +26,7 @@ mochikit.jar:
   content/tests/SimpleTest/MozillaLogger.js (../specialpowers/content/MozillaLogger.js)
   content/tests/SimpleTest/specialpowers.js (../specialpowers/content/specialpowers.js)
   content/tests/SimpleTest/SpecialPowersObserverAPI.js (../specialpowers/content/SpecialPowersObserverAPI.js)
-  content/tests/SimpleTest/specialpowersAPI.js (../specialpowers/content/specialpowersAPI.js)
+* content/tests/SimpleTest/specialpowersAPI.js (../specialpowers/content/specialpowersAPI.js)
   content/tests/SimpleTest/setup.js (tests/SimpleTest/setup.js)
   content/tests/SimpleTest/SimpleTest.js (tests/SimpleTest/SimpleTest.js)
   content/tests/SimpleTest/test.css (tests/SimpleTest/test.css)

testing/specialpowers/content/specialpowersAPI.js

@@ -1488,6 +1488,14 @@ SpecialPowersAPI.prototype = {
     return this._os;
   },
 
+  get isB2G() {
+#ifdef MOZ_B2G
+    return true;
+#else
+    return false;
+#endif
+  },
+
   addSystemEventListener: function(target, type, listener, useCapture) {
     Cc["@mozilla.org/eventlistenerservice;1"].
       getService(Ci.nsIEventListenerService).

testing/specialpowers/jar.mn

@@ -1,7 +1,7 @@
 specialpowers.jar:
 % content specialpowers %content/
   content/specialpowers.js (content/specialpowers.js)
-  content/specialpowersAPI.js (content/specialpowersAPI.js)
+* content/specialpowersAPI.js (content/specialpowersAPI.js)
   content/SpecialPowersObserverAPI.js (content/SpecialPowersObserverAPI.js)
   content/MozillaLogger.js (content/MozillaLogger.js)