Bug 1364987 - Remove the pref to allow APZ with webrender. r=rhunt

People seem to be turning on this pref in the wild and generating crash reports
which are wasting time and energy of people who have better things to do.

MozReview-Commit-ID: 5VfjKaDluYJ

--HG--
extra : rebase_source : fa2237835d842ddb118c6ba6096f6b703aef9d81

gfx/thebes/gfxPrefs.h

@@ -282,7 +282,6 @@ private:
   // The apz prefs are explained in AsyncPanZoomController.cpp
   DECL_GFX_PREF(Live, "apz.allow_checkerboarding",             APZAllowCheckerboarding, bool, true);
   DECL_GFX_PREF(Live, "apz.allow_immediate_handoff",           APZAllowImmediateHandoff, bool, true);
-  DECL_GFX_PREF(Once, "apz.allow_with_webrender",              APZAllowWithWebRender, bool, false);
   DECL_GFX_PREF(Live, "apz.allow_zooming",                     APZAllowZooming, bool, false);
   DECL_GFX_PREF(Live, "apz.axis_lock.breakout_angle",          APZAxisBreakoutAngle, float, float(M_PI / 8.0) /* 22.5 degrees */);
   DECL_GFX_PREF(Live, "apz.axis_lock.breakout_threshold",      APZAxisBreakoutThreshold, float, 1.0f / 32.0f);

modules/libpref/init/all.js

@@ -633,7 +633,6 @@ pref("layers.geometry.d3d11.enabled", true);
 // gfx/layers/apz/src/AsyncPanZoomController.cpp.
 pref("apz.allow_checkerboarding", true);
 pref("apz.allow_immediate_handoff", true);
-pref("apz.allow_with_webrender", false);
 pref("apz.allow_zooming", false);
 
 // Whether to lock touch scrolling to one axis at a time

widget/nsBaseWidget.cpp

@@ -1255,9 +1255,8 @@ void nsBaseWidget::CreateCompositor(int aWidth, int aHeight)
 
   bool enableWR = gfx::gfxVars::UseWebRender();
   bool enableAPZ = UseAPZ();
-  if (enableWR && !gfxPrefs::APZAllowWithWebRender()) {
-    // Disable APZ on widgets using WebRender, since it doesn't work yet. Allow
-    // it on non-WR widgets or if the pref forces it on.
+  if (enableWR) {
+    // Disable APZ on widgets using WebRender, since it doesn't work yet.
     enableAPZ = false;
   }
   CompositorOptions options(enableAPZ, enableWR);