Use const where possible for drawing parameters

They should never be modified by a Renderer, only read and copied.

Change-Id: I9d8d55dca19115ee9dfeb2bb3f092ba2fb327cd4
diff --git a/libs/hwui/TextDropShadowCache.cpp b/libs/hwui/TextDropShadowCache.cpp
index 6f27b36..4eec462 100644
--- a/libs/hwui/TextDropShadowCache.cpp
+++ b/libs/hwui/TextDropShadowCache.cpp
@@ -168,7 +168,7 @@
     mCache.clear();
 }
 
-ShadowTexture* TextDropShadowCache::get(SkPaint* paint, const char* text, uint32_t len,
+ShadowTexture* TextDropShadowCache::get(const SkPaint* paint, const char* text, uint32_t len,
         int numGlyphs, float radius, const float* positions) {
     ShadowText entry(paint, radius, len, text, positions);
     ShadowTexture* texture = mCache.get(entry);