Move canvas->surface association to the device subclasses

src/core/SkCanvas.cpp

Index: src/core/SkCanvas.cpp
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index 221ed93ac8c20122ebe47b1c6dccce8defcc3fb9..a8666c46864e8be5fff81058fb81063018b9354b 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -78,12 +78,6 @@ 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) {
@@ -409,13 +403,11 @@ 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);
@@ -440,8 +432,6 @@ SkBaseDevice* SkCanvas::init(SkBaseDevice* device, InitFlags flags) {
     fMCRec->fLayer = SkNEW_ARGS(DeviceCM, (NULL, 0, 0, NULL, NULL, fConservativeRasterClip));
     fMCRec->fTopLayer = fMCRec->fLayer;
 
-    fSurfaceBase = NULL;
-
     fClipStack.reset(SkNEW(SkClipStack));
 
     if (device) {
@@ -717,9 +707,6 @@ 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());
 }
@@ -1665,8 +1652,8 @@ void SkCanvas::drawSprite(const SkBitmap& bitmap, int left, int top, const SkPai
 //////////////////////////////////////////////////////////////////////////////
 
 void SkCanvas::onDiscard() {
-    if (fSurfaceBase) {
-        fSurfaceBase->aboutToDraw(SkSurface::kDiscard_ContentChangeMode);
+    if (this->getDevice()) {
+        this->getDevice()->discard();
     }
 }