Clean unused parameters, disable warnings

Change-Id: Iddb872f53075dd022eeef45265594d1c6a9e2bc0
diff --git a/libs/hwui/TextDropShadowCache.cpp b/libs/hwui/TextDropShadowCache.cpp
index 0b2c130..6f27b36 100644
--- a/libs/hwui/TextDropShadowCache.cpp
+++ b/libs/hwui/TextDropShadowCache.cpp
@@ -147,7 +147,7 @@
 // Callbacks
 ///////////////////////////////////////////////////////////////////////////////
 
-void TextDropShadowCache::operator()(ShadowText& text, ShadowTexture*& texture) {
+void TextDropShadowCache::operator()(ShadowText&, ShadowTexture*& texture) {
     if (texture) {
         mSize -= texture->bitmapSize;