Allow one-copy task tile worker pool to use compressed textures.

cc/base/switches.cc

Index: cc/base/switches.cc
diff --git a/cc/base/switches.cc b/cc/base/switches.cc
index 9cf6d5c470e6f1d78f4237ed5eac80b608aabef7..e73d17af6769734419bb7cafa0a0c5966d59871d 100644
--- a/cc/base/switches.cc
+++ b/cc/base/switches.cc
@@ -50,6 +50,9 @@ const char kStrictLayerPropertyChangeChecking[] =
 const char kEnablePropertyTreeVerification[] =
     "enable-property-tree-verification";
 
+// Compress tile textures for GPUs supporting it.
+const char kEnableTileCompression[] = "enable-tile-compression";
+
 // Use a BeginFrame signal from browser to renderer to schedule rendering.
 const char kEnableBeginFrameScheduling[] = "enable-begin-frame-scheduling";