[WIP] Add Context to SkDrawLooper.

src/effects/SkLayerDrawLooper.cpp

Index: src/effects/SkLayerDrawLooper.cpp
diff --git a/src/effects/SkLayerDrawLooper.cpp b/src/effects/SkLayerDrawLooper.cpp
index 6c7c3cef0cb04f2529fc3e21fd5688d3a7b19fed..449361edc03c60771bfd570efc5b79bbab2bc1e6 100644
--- a/src/effects/SkLayerDrawLooper.cpp
+++ b/src/effects/SkLayerDrawLooper.cpp
@@ -12,6 +12,7 @@
 #include "SkLayerDrawLooper.h"
 #include "SkString.h"
 #include "SkStringUtils.h"
+#include "SkTemplatesPriv.h"
 #include "SkUnPreMultiply.h"
 
 SkLayerDrawLooper::LayerInfo::LayerInfo() {
@@ -25,8 +26,7 @@ SkLayerDrawLooper::LayerInfo::LayerInfo() {
 SkLayerDrawLooper::SkLayerDrawLooper()
         : fRecs(NULL),
           fTopRec(NULL),
-          fCount(0),
-          fCurrRec(NULL) {
+          fCount(0) {
 }
 
 SkLayerDrawLooper::~SkLayerDrawLooper() {
@@ -76,9 +76,13 @@ SkPaint* SkLayerDrawLooper::addLayerOnTop(const LayerInfo& info) {
     return &rec->fPaint;
 }
 
-void SkLayerDrawLooper::init(SkCanvas* canvas) {
-    fCurrRec = fRecs;
+SkLayerDrawLooper::DrawContext* SkLayerDrawLooper::init(
+        SkCanvas* canvas, void* storage, size_t storageSize) const {
+    LayerDrawLooperContext* context;
+    SK_PLACEMENT_SAFE_NEW_ARGS(context, LayerDrawLooperContext, storage,
+                               storageSize, (this));
     canvas->save(SkCanvas::kMatrix_SaveFlag);
+    return context;
 }
 
 static SkColor xferColor(SkColor src, SkColor dst, SkXfermode::Mode mode) {
@@ -99,8 +103,8 @@ static SkColor xferColor(SkColor src, SkColor dst, SkXfermode::Mode mode) {
 // Even with kEntirePaint_Bits, we always ensure that the master paint's
 // text-encoding is respected, since that controls how we interpret the
 // text/length parameters of a draw[Pos]Text call.
-void SkLayerDrawLooper::ApplyInfo(SkPaint* dst, const SkPaint& src,
-                                  const LayerInfo& info) {
+void SkLayerDrawLooper::LayerDrawLooperContext::ApplyInfo(
+        SkPaint* dst, const SkPaint& src, const LayerInfo& info) {
 
     uint32_t mask = info.fFlagsMask;
     dst->setFlags((dst->getFlags() & ~mask) | (src.getFlags() & mask));
@@ -170,7 +174,11 @@ static void postTranslate(SkCanvas* canvas, SkScalar dx, SkScalar dy) {
     canvas->setMatrix(m);
 }
 
-bool SkLayerDrawLooper::next(SkCanvas* canvas, SkPaint* paint) {
+SkLayerDrawLooper::LayerDrawLooperContext::LayerDrawLooperContext(
+        const SkLayerDrawLooper* looper) : fCurrRec(looper->fRecs) {}
+
+bool SkLayerDrawLooper::LayerDrawLooperContext::next(SkCanvas* canvas,
+                                                     SkPaint* paint) {
     canvas->restore();
     if (NULL == fCurrRec) {
         return false;
@@ -183,7 +191,8 @@ bool SkLayerDrawLooper::next(SkCanvas* canvas, SkPaint* paint) {
         postTranslate(canvas, fCurrRec->fInfo.fOffset.fX,
                       fCurrRec->fInfo.fOffset.fY);
     } else {
-        canvas->translate(fCurrRec->fInfo.fOffset.fX, fCurrRec->fInfo.fOffset.fY);
+        canvas->translate(fCurrRec->fInfo.fOffset.fX,
+                          fCurrRec->fInfo.fOffset.fY);
     }
     fCurrRec = fCurrRec->fNext;
 
@@ -225,8 +234,7 @@ SkLayerDrawLooper::SkLayerDrawLooper(SkReadBuffer& buffer)
         : INHERITED(buffer),
           fRecs(NULL),
           fTopRec(NULL),
-          fCount(0),
-          fCurrRec(NULL) {
+          fCount(0) {
     int count = buffer.readInt();
 
     for (int i = 0; i < count; i++) {