Bug 1217515 - Clean up the way touch event support is configured. r=roc

- all.js now sets dom.w3c_touch_events.enabled to auto-detect on all
  platforms except windows and mac
- auto-detect always returns true for android and b2g
- graphene and tests override the all.js pref with their own value

b2g/app/b2g.js

@@ -344,10 +344,6 @@ pref("image.mem.surfacecache.size_factor", 8);  // 1/8 of main memory
 pref("image.mem.surfacecache.discard_factor", 2);  // Discard 1/2 of the surface cache at a time.
 pref("image.mem.surfacecache.min_expiration_ms", 86400000); // 24h, we rely on the out of memory hook
 
-// XXX this isn't a good check for "are touch events supported", but
-// we don't really have a better one at the moment.
-// enable touch events interfaces
-pref("dom.w3c_touch_events.enabled", 1);
 pref("dom.w3c_touch_events.safetyX", 0); // escape borders in units of 1/240"
 pref("dom.w3c_touch_events.safetyY", 120); // escape borders in units of 1/240"
 

browser/app/profile/firefox.js

@@ -486,10 +486,6 @@ pref("dom.disable_window_move_resize",            false);
 // prevent JS from monkeying with window focus, etc
 pref("dom.disable_window_flip",                   true);
 
-// Disable touch events on Desktop Firefox by default until they are properly
-// supported (bug 736048)
-pref("dom.w3c_touch_events.enabled",        0);
-
 // popups.policy 1=allow,2=reject
 pref("privacy.popups.policy",               1);
 pref("privacy.popups.usecustom",            true);

dom/events/TouchEvent.cpp

@@ -181,7 +181,10 @@ TouchEvent::PrefEnabled(JSContext* aCx, JSObject* aGlobal)
   int32_t flag = 0;
   if (NS_SUCCEEDED(Preferences::GetInt("dom.w3c_touch_events.enabled", &flag))) {
     if (flag == 2) {
-#if defined(XP_WIN) || MOZ_WIDGET_GTK == 3
+#if defined(MOZ_B2G) || defined(MOZ_WIDGET_ANDROID)
+      // Touch support is always enabled on B2G and android.
+      prefValue = true;
+#elif defined(XP_WIN) || MOZ_WIDGET_GTK == 3
       static bool sDidCheckTouchDeviceSupport = false;
       static bool sIsTouchDeviceSupportPresent = false;
       // On Windows and GTK3 we auto-detect based on device support.

mobile/android/app/mobile.js

@@ -605,9 +605,6 @@ pref("image.downscale-during-decode.enabled", true);
 pref("shumway.disabled", true);
 #endif
 
-// enable touch events interfaces
-pref("dom.w3c_touch_events.enabled", 1);
-
 #ifdef MOZ_SAFE_BROWSING
 pref("browser.safebrowsing.enabled", true);
 pref("browser.safebrowsing.malware.enabled", true);

mobile/android/b2gdroid/app/b2gdroid.js

@@ -606,9 +606,6 @@ pref("image.downscale-during-decode.enabled", true);
 pref("shumway.disabled", true);
 #endif
 
-// enable touch events interfaces
-pref("dom.w3c_touch_events.enabled", 1);
-
 #ifdef MOZ_SAFE_BROWSING
 pref("browser.safebrowsing.enabled", true);
 pref("browser.safebrowsing.malware.enabled", true);

modules/libpref/init/all.js

@@ -4543,12 +4543,11 @@ pref("dom.mozSettings.enabled", false);
 pref("dom.mozPermissionSettings.enabled", false);
 
 // W3C touch events
-// 0 - disabled, 1 - enabled, 2 - autodetect (win/gtk3)
-#ifdef XP_WIN
-pref("dom.w3c_touch_events.enabled", 2);
-#endif
-
-#if MOZ_WIDGET_GTK == 3
+// 0 - disabled, 1 - enabled, 2 - autodetect
+// Enabling it for Windows is tracked by bug 736048.
+#if defined(XP_WIN) || defined(XP_MACOSX)
+pref("dom.w3c_touch_events.enabled", 0);
+#else
 pref("dom.w3c_touch_events.enabled", 2);
 #endif