Bug 1045680 - Instead of checking <= 256mb, check < 512mb. r=jwillcox

gfx/thebes/gfxPlatform.cpp

@@ -856,8 +856,9 @@ gfxPlatform::InitializeSkiaCacheLimits()
     if (usingDynamicCache) {
       uint32_t totalMemory = mozilla::hal::GetTotalSystemMemory();
 
-      if (totalMemory <= 256*1024*1024) {
-        // We need a very minimal cache on 256 meg devices
+      if (totalMemory < 512*1024*1024) {
+        // We need a very minimal cache on anything smaller than 512mb.
+        // Note the large jump as we cross 512mb (from 2mb to 32mb).
         cacheSizeLimit = 2*1024*1024;
       } else if (totalMemory > 0) {
         cacheSizeLimit = totalMemory / 16;