Implement SkBaseDevice snapshot support

src/core/SkCanvas.cpp

Index: src/core/SkCanvas.cpp
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index a16a1a2c5e4a91573e91a9eca26c6a60ad2506c8..3734de1e2feb575e1dc6b451cbf8b7bb23077eae 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -80,12 +80,6 @@ bool SkCanvas::Internal_Private_GetTreatSpriteAsBitmap() {
 
 typedef SkTLazy<SkPaint> SkLazyPaint;
 
-void SkCanvas::predrawNotify() {
-    if (fSurfaceBase) {
-        fSurfaceBase->aboutToDraw(SkSurface::kRetain_ContentChangeMode);
-    }
-}
-
 ///////////////////////////////////////////////////////////////////////////////
 
 static uint32_t filter_paint_flags(const SkSurfaceProps& props, uint32_t flags) {
@@ -410,13 +404,11 @@ bool AutoDrawLooper::doNext(SkDrawFilter::Type drawType) {
 ////////// macros to place around the internal draw calls //////////////////
 
 #define LOOPER_BEGIN_DRAWDEVICE(paint, type)                        \
-    this->predrawNotify();                                          \
     AutoDrawLooper  looper(this, fProps, paint, true);              \
     while (looper.next(type)) {                                     \
         SkDrawIter          iter(this);
 
 #define LOOPER_BEGIN(paint, type, bounds)                           \
-    this->predrawNotify();                                          \
     AutoDrawLooper  looper(this, fProps, paint, false, bounds);     \
     while (looper.next(type)) {                                     \
         SkDrawIter          iter(this);
@@ -441,8 +433,6 @@ SkBaseDevice* SkCanvas::init(SkBaseDevice* device, InitFlags flags) {
     fMCRec->fLayer = SkNEW_ARGS(DeviceCM, (NULL, NULL, NULL, fConservativeRasterClip));
     fMCRec->fTopLayer = fMCRec->fLayer;
 
-    fSurfaceBase = NULL;
-
     fClipStack.reset(SkNEW(SkClipStack));
 
     if (device) {
@@ -718,9 +708,6 @@ bool SkCanvas::writePixels(const SkImageInfo& origInfo, const void* pixels, size
     // here x,y are either 0 or negative
     pixels = ((const char*)pixels - y * rowBytes - x * info.bytesPerPixel());
 
-    // Tell our owning surface to bump its generation ID
-    this->predrawNotify();
-
     // The device can assert that the requested area is always contained in its bounds
     return device->writePixels(info, pixels, rowBytes, target.x(), target.y());
 }
@@ -1116,6 +1103,8 @@ void SkCanvas::internalDrawDevice(SkBaseDevice* srcDev, int x, int y,
         paint = &tmp;
     }
 
+    SkAutoTUnref<SkImage> srcImage;
+
     LOOPER_BEGIN_DRAWDEVICE(*paint, SkDrawFilter::kBitmap_Type)
     while (iter.next()) {
         SkBaseDevice* dstDev = iter.fDevice;
@@ -1126,17 +1115,36 @@ void SkCanvas::internalDrawDevice(SkBaseDevice* srcDev, int x, int y,
             SkDeviceImageFilterProxy proxy(dstDev, fProps);
             SkBitmap dst;
             SkIPoint offset = SkIPoint::Make(0, 0);
-            const SkBitmap& src = srcDev->accessBitmap(false);
+            if (NULL == srcImage) {
+                srcImage.reset(srcDev->newImageSnapshot());
+                if (NULL == srcImage) {
+                    return;
+                }
+            }
             SkMatrix matrix = *iter.fMatrix;
             matrix.postTranslate(SkIntToScalar(-pos.x()), SkIntToScalar(-pos.y()));
             SkIRect clipBounds = SkIRect::MakeWH(srcDev->width(), srcDev->height());
             SkAutoTUnref<SkImageFilter::Cache> cache(dstDev->getImageFilterCache());
             SkImageFilter::Context ctx(matrix, clipBounds, cache.get());
-            if (filter->filterImage(&proxy, src, ctx, &dst, &offset)) {
-                SkPaint tmpUnfiltered(*paint);
-                tmpUnfiltered.setImageFilter(NULL);
-                dstDev->drawSprite(iter, dst, pos.x() + offset.x(), pos.y() + offset.y(),
-                                   tmpUnfiltered);
+            SkBitmap srcBitmap;  // TODO: remove once filters accept SkImage
+#if SK_SUPPORT_GPU
+            // TODO: Gpu devices need bitmap that came from gpu, not through
+            // getROPixels. Remove once filters accept SkImage.
+            if (NULL != srcImage->getTexture()) {
+                SkImageFilter::WrapTexture(srcImage->getTexture(), srcImage->width(),
+                                           srcImage->height(), &srcBitmap);
+            } else
+#endif
+            {
+                as_IB(srcImage)->getROPixels(&srcBitmap);
+            }
+            if (!srcBitmap.empty()) {
+                if (filter->filterImage(&proxy, srcBitmap, ctx, &dst, &offset)) {
+                    SkPaint tmpUnfiltered(*paint);
+                    tmpUnfiltered.setImageFilter(NULL);
+                    dstDev->drawSprite(iter, dst, pos.x() + offset.x(), pos.y() + offset.y(),
+                                       tmpUnfiltered);
+                }
             }
         } else {
             dstDev->drawDevice(iter, srcDev, pos.x(), pos.y(), *paint);
@@ -1718,8 +1726,8 @@ void SkCanvas::drawImageAsSprite(const SkImage& image, int left, int top, const
 //////////////////////////////////////////////////////////////////////////////
 
 void SkCanvas::onDiscard() {
-    if (fSurfaceBase) {
-        fSurfaceBase->aboutToDraw(SkSurface::kDiscard_ContentChangeMode);
+    if (NULL != this->getDevice()) {
+        this->getDevice()->discard();
     }
 }