Removed unused parameters

I removed unused parameters wherever it was trivial to do so.
Review URL: https://codereview.chromium.org/12469002

git-svn-id: http://skia.googlecode.com/svn/trunk@8068 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrTHashCache.h b/src/gpu/GrTHashCache.h
index 3427ffe..6bd58c2 100644
--- a/src/gpu/GrTHashCache.h
+++ b/src/gpu/GrTHashCache.h
@@ -20,7 +20,7 @@
 template <typename T> class GrTDefaultFindFunctor {
 public:
     // always accept the first element examined
-    bool operator()(const T* elem) const { return true; }
+    bool operator()(const T*) const { return true; }
 };
 
 /**