Refactor bitmap scaler to make it easier to migrate rest of chrome to use it

src/core/SkBitmapScaler.cpp

Index: src/core/SkBitmapScaler.cpp
diff --git a/src/core/SkBitmapScaler.cpp b/src/core/SkBitmapScaler.cpp
index be32a891fcd8c4a9226514ecc4806179a889ddd4..35e101efa964238f7f05a13de849d396a636d759 100644
--- a/src/core/SkBitmapScaler.cpp
+++ b/src/core/SkBitmapScaler.cpp
@@ -246,9 +246,11 @@ bool SkBitmapScaler::Resize(SkBitmap* resultPtr,
                             const SkBitmap& source,
                             ResizeMethod method,
                             float destWidth, float destHeight,
-                            const SkConvolutionProcs& convolveProcs,
                             SkBitmap::Allocator* allocator) {
 
+  SkConvolutionProcs convolveProcs= { 0, NULL, NULL, NULL, NULL };
+  PlatformConvolutionProcs(&convolveProcs);
+
   SkRect destSubset = { 0, 0, destWidth, destHeight };
 
   // Ensure that the ResizeMethod enumeration is sound.