Enable unused param checking for public includes.

include/core/SkDevice.h

Index: include/core/SkDevice.h
diff --git a/include/core/SkDevice.h b/include/core/SkDevice.h
index 43cb32c8c92574f0ed44fd0cc2ee111752f36f5b..471a76be8eaa82b22992a6e2de4fd58c538ac2e9 100644
--- a/include/core/SkDevice.h
+++ b/include/core/SkDevice.h
@@ -281,8 +281,8 @@ protected:
      *  it just returns false and leaves result and offset unchanged.
      */
     virtual bool filterImage(const SkImageFilter*, const SkBitmap&,
-                             const SkImageFilter::Context& ctx,
-                             SkBitmap* result, SkIPoint* offset) {
+                             const SkImageFilter::Context&,
+                             SkBitmap* /*result*/, SkIPoint* /*offset*/) {
         return false;
     }
 
@@ -352,7 +352,7 @@ protected:
         const SkPixelGeometry fPixelGeometry;
     };
 
-    virtual SkBaseDevice* onCreateCompatibleDevice(const CreateInfo& cinfo) {
+    virtual SkBaseDevice* onCreateCompatibleDevice(const CreateInfo&) {
         return NULL;
     }