Add GrSurface::savePixels().

include/gpu/GrSurface.h

Index: include/gpu/GrSurface.h
diff --git a/include/gpu/GrSurface.h b/include/gpu/GrSurface.h
index 3aa498b6110bb00c4a0b130aedc031678ec58705..7d8a9240d3b68729eebff412d5096022a0fad892 100644
--- a/include/gpu/GrSurface.h
+++ b/include/gpu/GrSurface.h
@@ -15,6 +15,7 @@
 
 class GrTexture;
 class GrRenderTarget;
+class GrDrawState;
 
 class GrSurface : public GrResource {
 public:
@@ -126,6 +127,12 @@ public:
                              size_t rowBytes = 0,
                              uint32_t pixelOpsFlags = 0) = 0;
 
+    /**
+     * Write the contents of the surface to a PNG. Returns true if successful.
+     * @param filename      Full path to desired file
+     */
+    bool savePixels(const char* filename);
+
 protected:
     GrSurface(GrGpu* gpu, bool isWrapped, const GrTextureDesc& desc)
     : INHERITED(gpu, isWrapped)