Put meta viewport support behind a pref (bug 1092450, r=kats).

--HG--
extra : rebase_source : 888513255b2d672643beb9933ebb67ac6a2452ca

b2g/app/b2g.js

@@ -433,8 +433,11 @@ pref("dom.mozBrowserFramesEnabled", true);
 pref("dom.ipc.processCount", 100000);
 
 pref("dom.ipc.browser_frames.oop_by_default", false);
+
 pref("dom.browser_frames.useAsyncPanZoom", true);
 
+pref("dom.meta-viewport.enabled", true);
+
 // SMS/MMS
 pref("dom.sms.enabled", true);
 

dom/base/nsDocument.cpp

@@ -7682,6 +7682,13 @@ nsDocument::GetViewportInfo(const ScreenIntSize& aDisplaySize)
   CSSToScreenScale defaultScale = layoutDeviceScale
                                 * LayoutDeviceToScreenScale(1.0);
 
+  if (!Preferences::GetBool("dom.meta-viewport.enabled", false)) {
+    return nsViewportInfo(aDisplaySize,
+                          defaultScale,
+                          /*allowZoom*/ false,
+                          /*allowDoubleTapZoom*/ true);
+  }
+
   // In cases where the width of the CSS viewport is less than or equal to the width
   // of the display (i.e. width <= device-width) then we disable double-tap-to-zoom
   // behaviour. See bug 941995 for details.

modules/libpref/init/all.js

@@ -4410,3 +4410,6 @@ pref("dom.beforeAfterKeyboardEvent.enabled", false);
 #ifdef XP_MACOSX
 pref("intl.collation.mac.use_icu", true);
 #endif
+
+// Enable meta-viewport support in remote APZ-enabled frames.
+pref("dom.meta-viewport.enabled", false);