Bug 979084 - Adjust the displayport when one axis is clipped by default on b2g. r=ajones

Change the default displayport settings to redistribute wasted displayport area
from one axis to the other and adjust displayport size accordingly on b2g.

b2g/app/b2g.js

@@ -874,6 +874,14 @@ pref("apz.pan_repaint_interval", 16);
 // to avoid checkerboarding.  Note, float value must be set as a string.
 pref("apz.max_velocity_pixels_per_ms", "6.0");
 
+// Tweak default displayport values to reduce the risk of running out of
+// memory when zooming in
+pref("apz.x_skate_size_multiplier", "1.25");
+pref("apz.y_skate_size_multiplier", "1.5");
+pref("apz.x_stationary_size_multiplier", "1.5");
+pref("apz.y_stationary_size_multiplier", "1.8");
+pref("apz.enlarge_displayport_when_clipped", true);
+
 // This preference allows FirefoxOS apps (and content, I think) to force
 // the use of software (instead of hardware accelerated) 2D canvases by
 // creating a context like this: