Purge cached resources on SkImage destruction.

src/image/SkImage.cpp

Index: src/image/SkImage.cpp
diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index 654b848fce22073ba274c57cbe0768c3464093dc..6f4655758e36cb7b50a565f514655cb51921db75 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -6,6 +6,7 @@
  */
 
 #include "SkBitmap.h"
+#include "SkBitmapCache.h"
 #include "SkCanvas.h"
 #include "SkData.h"
 #include "SkImageGenerator.h"
@@ -210,6 +211,22 @@ static bool raster_canvas_supports(const SkImageInfo& info) {
     return false;
 }
 
+static SkSurfaceProps copy_or_safe_defaults(const SkSurfaceProps* props) {
+    return props ? *props : SkSurfaceProps(0, kUnknown_SkPixelGeometry);
+}
+
+SkImage_Base::SkImage_Base(int width, int height, uint32_t uniqueID, const SkSurfaceProps* props)
+    : INHERITED(width, height, uniqueID)
+    , fProps(copy_or_safe_defaults(props))
+    , fAddedToCache(false)
+{ }
+
+SkImage_Base::~SkImage_Base() {
+    if (fAddedToCache.load()) {
+        SkNotifyBitmapGenIDIsStale(this->uniqueID());
+    }
+}
+
 bool SkImage_Base::onReadPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
                                 int srcX, int srcY) const {
     if (!raster_canvas_supports(dstInfo)) {