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 0db15030d5b5a661a16398c420e79b4ad6072732..2d6ef08baf2bc843334d080d6d8243451e1d3bda 100644
--- a/cc/base/switches.cc
+++ b/cc/base/switches.cc
@@ -44,6 +44,9 @@ const char kStrictLayerPropertyChangeChecking[] =
 const char kEnablePropertyTreeVerification[] =
     "enable-property-tree-verification";
 
+// Compress tile textures for GPUs supporting it.
+const char kEnableTileCompression[] = "enable-tile-compression";
+
 // Disable partial swap which is needed for some OpenGL drivers / emulators.
 const char kUIDisablePartialSwap[] = "ui-disable-partial-swap";