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/font/Font.h b/libs/hwui/font/Font.h
index f68b430..02197bc 100644
--- a/libs/hwui/font/Font.h
+++ b/libs/hwui/font/Font.h
@@ -77,11 +77,11 @@
 
     ~Font();
 
-    void render(SkPaint* paint, const char* text, uint32_t start, uint32_t len,
+    void render(const SkPaint* paint, const char* text, uint32_t start, uint32_t len,
             int numGlyphs, int x, int y, const float* positions);
 
-    void render(SkPaint* paint, const char* text, uint32_t start, uint32_t len,
-            int numGlyphs, SkPath* path, float hOffset, float vOffset);
+    void render(const SkPaint* paint, const char* text, uint32_t start, uint32_t len,
+            int numGlyphs, const SkPath* path, float hOffset, float vOffset);
 
     const Font::FontDescription& getDescription() const {
         return mDescription;
@@ -106,20 +106,20 @@
         MEASURE,
     };
 
-    void precache(SkPaint* paint, const char* text, int numGlyphs);
+    void precache(const SkPaint* paint, const char* text, int numGlyphs);
 
-    void render(SkPaint* paint, const char *text, uint32_t start, uint32_t len,
+    void render(const SkPaint* paint, const char *text, uint32_t start, uint32_t len,
             int numGlyphs, int x, int y, RenderMode mode, uint8_t *bitmap,
             uint32_t bitmapW, uint32_t bitmapH, Rect *bounds, const float* positions);
 
-    void measure(SkPaint* paint, const char* text, uint32_t start, uint32_t len,
+    void measure(const SkPaint* paint, const char* text, uint32_t start, uint32_t len,
             int numGlyphs, Rect *bounds, const float* positions);
 
     void invalidateTextureCache(CacheTexture* cacheTexture = NULL);
 
-    CachedGlyphInfo* cacheGlyph(SkPaint* paint, glyph_t glyph, bool precaching);
-    void updateGlyphCache(SkPaint* paint, const SkGlyph& skiaGlyph, SkGlyphCache* skiaGlyphCache,
-            CachedGlyphInfo* glyph, bool precaching);
+    CachedGlyphInfo* cacheGlyph(const SkPaint* paint, glyph_t glyph, bool precaching);
+    void updateGlyphCache(const SkPaint* paint, const SkGlyph& skiaGlyph,
+            SkGlyphCache* skiaGlyphCache, CachedGlyphInfo* glyph, bool precaching);
 
     void measureCachedGlyph(CachedGlyphInfo* glyph, int x, int y,
             uint8_t *bitmap, uint32_t bitmapW, uint32_t bitmapH,
@@ -136,7 +136,8 @@
     void drawCachedGlyph(CachedGlyphInfo* glyph, float x, float hOffset, float vOffset,
             SkPathMeasure& measure, SkPoint* position, SkVector* tangent);
 
-    CachedGlyphInfo* getCachedGlyph(SkPaint* paint, glyph_t textUnit, bool precaching = false);
+    CachedGlyphInfo* getCachedGlyph(const SkPaint* paint, glyph_t textUnit,
+            bool precaching = false);
 
     FontRenderer* mState;
     FontDescription mDescription;