Extract most of the mutable state of SkShader into a separate Context object.

src/core/SkBitmapProcState.cpp

Index: src/core/SkBitmapProcState.cpp
diff --git a/src/core/SkBitmapProcState.cpp b/src/core/SkBitmapProcState.cpp
index cdc582bfeec64a70791d0ecb615186b98296e639..b3431f4eb84e267e6bae7769e7db7d44d8a6fd39 100644
--- a/src/core/SkBitmapProcState.cpp
+++ b/src/core/SkBitmapProcState.cpp
@@ -377,6 +377,26 @@ SkBitmapProcState::~SkBitmapProcState() {
     SkDELETE(fBitmapFilter);
 }
 
+SkBitmapProcState::SkBitmapProcState(const SkBitmapProcState& src)
+    : fInvMatrix(src.fInvMatrix), fInvProc(src.fInvProc),
+      fInvSxFractionalInt(src.fInvSxFractionalInt), fInvKyFractionalInt(src.fInvKyFractionalInt),
+      fTileProcX(src.fTileProcX), fTileProcY(src.fTileProcY),
+      fTileLowBitsProcX(src.fTileLowBitsProcX), fTileLowBitsProcY(src.fTileLowBitsProcY),
+      fIntTileProcY(src.fIntTileProcY), fFilterOneX(src.fFilterOneX), fFilterOneY(src.fFilterOneY),
+      fPaintPMColor(src.fPaintPMColor), fInvSx(src.fInvSx), fInvKy(src.fInvKy),
+      fAlphaScale(src.fAlphaScale), fInvType(src.fInvType),
+      fTileModeX(src.fTileModeX), fTileModeY(src.fTileModeY), fFilterLevel(src.fFilterLevel),
+      fShaderProc32(src.fShaderProc32), fShaderProc16(src.fShaderProc16),
+      fMatrixProc(src.fMatrixProc), fSampleProc32(src.fSampleProc32),
+      fSampleProc16(src.fSampleProc16), fOrigBitmap(src.fOrigBitmap),
+      fScaledBitmap(src.fScaledBitmap)
+{
+    // TODO(dominikg): Doesn't work yet. Assert in SkBitmapProcShader.cpp on line 224 fails.
+    fBitmap = src.fBitmap == &src.fOrigBitmap ? &fOrigBitmap : &fScaledBitmap;
+
+    fBitmapFilter = src.fBitmapFilter;
+}
+
 bool SkBitmapProcState::chooseProcs(const SkMatrix& inv, const SkPaint& paint) {
     SkASSERT(fOrigBitmap.width() && fOrigBitmap.height());
 
@@ -398,6 +418,7 @@ bool SkBitmapProcState::chooseProcs(const SkMatrix& inv, const SkPaint& paint) {
     }
     // The above logic should have always assigned fBitmap, but in case it
     // didn't, we check for that now...
+    // TODO(dominikg): Ask humper@ if we can just use an SkASSERT(fBitmap)?
     if (NULL == fBitmap) {
         return false;
     }
@@ -480,6 +501,7 @@ bool SkBitmapProcState::chooseProcs(const SkMatrix& inv, const SkPaint& paint) {
     // shader will perform.
 
     fMatrixProc = this->chooseMatrixProc(trivialMatrix);
+    // TODO(dominikg): SkASSERT(fMatrixProc) instead? chooseMatrixProc never returns NULL.
     if (NULL == fMatrixProc) {
         return false;
     }
@@ -521,6 +543,7 @@ bool SkBitmapProcState::chooseProcs(const SkMatrix& inv, const SkPaint& paint) {
                 fPaintPMColor = SkPreMultiplyColor(paint.getColor());
                 break;
             default:
+                // TODO(dominikg): Should we ever get here? SkASSERT(false) instead?
                 return false;
         }