Frameworks/base: Wall Werror in libs/hwui

Turn on -Wall -Werror in libs/hwui. Fix errors.

Change-Id: I74962d08c889712dacbd0d86d6760fc10802b6bd
diff --git a/libs/hwui/font/Font.cpp b/libs/hwui/font/Font.cpp
index ba878bac..bf55558 100644
--- a/libs/hwui/font/Font.cpp
+++ b/libs/hwui/font/Font.cpp
@@ -378,7 +378,7 @@
             break;
         }
 
-        CachedGlyphInfo* cachedGlyph = getCachedGlyph(paint, glyph, true);
+        getCachedGlyph(paint, glyph, true);
         glyphsCount++;
     }
 }
@@ -403,8 +403,6 @@
     text += start;
     int glyphsCount = 0;
 
-    const SkPaint::Align align = paint->getTextAlign();
-
     while (glyphsCount < numGlyphs) {
         glyph_t glyph = GET_GLYPH(text);