Expire resources in ResourcePool after non-use

cc/base/switches.cc

Index: cc/base/switches.cc
diff --git a/cc/base/switches.cc b/cc/base/switches.cc
index b95ac111cc4d78e133e68d26a3aff72e42fdd0c4..bd980507a7eb3226026ae171c08fd02d861cf98a 100644
--- a/cc/base/switches.cc
+++ b/cc/base/switches.cc
@@ -35,10 +35,6 @@ const char kTopControlsShowThreshold[] = "top-controls-show-threshold";
 // complete, such as --slow-down-raster-scale-factor=25.
 const char kSlowDownRasterScaleFactor[] = "slow-down-raster-scale-factor";
 
-// The amount of unused resource memory compositor is allowed to keep around.
-const char kMaxUnusedResourceMemoryUsagePercentage[] =
-    "max-unused-resource-memory-usage-percentage";
-
 // Causes the compositor to render to textures which are then sent to the parent
 // through the texture mailbox mechanism.
 // Requires --enable-compositor-frame-message.