Add image->bitmap

src/image/SkImage.cpp

Index: src/image/SkImage.cpp
diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index d3533a9a4a58cd7ab7d87ada6ec5bc4931314f65..2152010c749e18a9a6ca3ac20f4675f2e4f8662a 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -263,6 +263,21 @@ SkImage* SkImage::NewFromBitmap(const SkBitmap& bm) {
     return SkNewImageFromRasterBitmap(bm, false, NULL);
 }
 
+bool SkImage::asBitmap(SkBitmap* bitmap, AsBitmapMode mode) const {
+    return as_IB(this)->onAsBitmap(bitmap, mode);
+}
+
+bool SkImage_Base::onAsBitmap(SkBitmap* bitmap, AsBitmapMode) const {
+    // As the base-class, all we can do is make a copy (regardless of mode).
+    // Subclasses that want to be more optimal should override.
+    SkImageInfo info = SkImageInfo::MakeN32(this->width(), this->height(),
+                                    this->isOpaque() ? kOpaque_SkAlphaType : kPremul_SkAlphaType);
+    if (!bitmap->tryAllocPixels(info)) {
+        return false;
+    }
+    return this->readPixels(bitmap->info(), bitmap->getPixels(), bitmap->rowBytes(), 0, 0);
+}
+
 //////////////////////////////////////////////////////////////////////////////////////
 
 #if !SK_SUPPORT_GPU