Use SkShader's localMat for SkLocalMatrixShader.

Cherry-pick of https://codereview.chromium.org/386693003/

Instead of setting SkShader::fLocalMatrix to Identity and storing
a separate SkMatrix inside SkLocalMatrixShader, reuse
SkShader::fLocalMatrix.

Conflicts:
	src/core/SkLocalMatrixShader.h

BUG:14315916

Change-Id: I673801444f0a8fd4f192b5b7effdde1aa83e702b

2 files changed, 6 insertions, 9 deletions

diff --git a/src/core/SkLocalMatrixShader.cpp b/src/core/SkLocalMatrixShader.cpp
index 53580e6ac9..afa782801d 100644
--- a/src/core/SkLocalMatrixShader.cpp
+++ b/src/core/SkLocalMatrixShader.cpp
@@ -8,7 +8,6 @@
 #include "SkLocalMatrixShader.h"
 
 SkLocalMatrixShader::SkLocalMatrixShader(SkReadBuffer& buffer) : INHERITED(buffer) {
-    buffer.readMatrix(&fProxyLocalMatrix);
     fProxyShader.reset(buffer.readShader());
     if (NULL == fProxyShader.get()) {
         sk_throw();
@@ -17,7 +16,6 @@ SkLocalMatrixShader::SkLocalMatrixShader(SkReadBuffer& buffer) : INHERITED(buffe
 
 void SkLocalMatrixShader::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
-    buffer.writeMatrix(fProxyLocalMatrix);
     buffer.writeFlattenable(fProxyShader.get());
 }
 
@@ -26,10 +24,10 @@ SkShader::Context* SkLocalMatrixShader::onCreateContext(const ContextRec& rec,
     ContextRec newRec(rec);
     SkMatrix tmp;
     if (rec.fLocalMatrix) {
-        tmp.setConcat(fProxyLocalMatrix, *rec.fLocalMatrix);
+        tmp.setConcat(this->getLocalMatrix(), *rec.fLocalMatrix);
         newRec.fLocalMatrix = &tmp;
     } else {
-        newRec.fLocalMatrix = &fProxyLocalMatrix;
+        newRec.fLocalMatrix = &this->getLocalMatrix();
     }
     return fProxyShader->createContext(newRec, storage);
 }
diff --git a/src/core/SkLocalMatrixShader.h b/src/core/SkLocalMatrixShader.h
index 1143f062d3..66d0c33e33 100644
--- a/src/core/SkLocalMatrixShader.h
+++ b/src/core/SkLocalMatrixShader.h
@@ -15,8 +15,8 @@
 class SkLocalMatrixShader : public SkShader {
 public:
     SkLocalMatrixShader(SkShader* proxy, const SkMatrix& localMatrix)
-    : fProxyShader(SkRef(proxy))
-    , fProxyLocalMatrix(localMatrix)
+    : INHERITED(&localMatrix)
+    , fProxyShader(SkRef(proxy))
     {}
 
     virtual size_t contextSize() const SK_OVERRIDE {
@@ -36,7 +36,7 @@ public:
     
     virtual bool asNewEffect(GrContext* context, const SkPaint& paint, const SkMatrix* localMatrix,
                              GrColor* grColor, GrEffectRef** grEffect) const SK_OVERRIDE {
-        SkMatrix tmp = fProxyLocalMatrix;
+        SkMatrix tmp = this->getLocalMatrix();
         if (localMatrix) {
             tmp.preConcat(*localMatrix);
         }
@@ -55,7 +55,7 @@ public:
     
     virtual SkShader* refAsALocalMatrixShader(SkMatrix* localMatrix) const SK_OVERRIDE {
         if (localMatrix) {
-            *localMatrix = fProxyLocalMatrix;
+            *localMatrix = this->getLocalMatrix();
         }
         return SkRef(fProxyShader.get());
     }
@@ -70,7 +70,6 @@ protected:
 
 private:
     SkAutoTUnref<SkShader> fProxyShader;
-    SkMatrix  fProxyLocalMatrix;
 
     typedef SkShader INHERITED;
 };