Add missing dependency to unbreak NOGPU build.

BUG=

Review URL: https://codereview.chromium.org/23527004

git-svn-id: http://skia.googlecode.com/svn/trunk@11188 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/benchmain.cpp b/bench/benchmain.cpp
index 289d5cb..44bc0da 100644
--- a/bench/benchmain.cpp
+++ b/bench/benchmain.cpp
@@ -21,6 +21,7 @@
 #include "SkBenchmark.h"
 #include "SkBitmapDevice.h"
 #include "SkCanvas.h"
+#include "SkColorPriv.h"
 #include "SkCommandLineFlags.h"
 #include "SkDeferredCanvas.h"
 #include "SkGraphics.h"