Adding 'static' to eleminate compile warning on mac

Unreviewed.

git-svn-id: http://skia.googlecode.com/svn/trunk@8649 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/DeferredCanvasTest.cpp b/tests/DeferredCanvasTest.cpp
index 37e6721..1e23457 100644
--- a/tests/DeferredCanvasTest.cpp
+++ b/tests/DeferredCanvasTest.cpp
@@ -476,7 +476,7 @@
 // Returns an opaque pointer which, either points to a GrTexture or RAM pixel
 // buffer. Used to test pointer equality do determine whether a surface points
 // to the same pixel data storage as before.
-PixelPtr getSurfacePixelPtr(SkSurface* surface, bool useGpu) {
+static PixelPtr getSurfacePixelPtr(SkSurface* surface, bool useGpu) {
     return useGpu ? surface->getCanvas()->getDevice()->accessBitmap(false).getTexture() :
         surface->getCanvas()->getDevice()->accessBitmap(false).getPixels();
 }