Simplify flattening to just write enough to call the factory

src/core/SkShader.cpp

Index: src/core/SkShader.cpp
diff --git a/src/core/SkShader.cpp b/src/core/SkShader.cpp
index d533cd69b42208b4d5c170d73e055a44f7821eb2..d55ac5babf4427886234112af3a8bb86cf8fd4b2 100644
--- a/src/core/SkShader.cpp
+++ b/src/core/SkShader.cpp
@@ -45,6 +45,7 @@ SkShader::SkShader(const SkMatrix* localMatrix) {
     }
 }
 
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 SkShader::SkShader(SkReadBuffer& buffer) : INHERITED(buffer) {
     inc_shader_counter();
     if (buffer.readBool()) {
@@ -53,6 +54,7 @@ SkShader::SkShader(SkReadBuffer& buffer) : INHERITED(buffer) {
         fLocalMatrix.reset();
     }
 }
+#endif
 
 SkShader::~SkShader() {
     dec_shader_counter();
@@ -254,6 +256,7 @@ bool SkColorShader::isOpaque() const {
     return SkColorGetA(fColor) == 255;
 }
 
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 SkColorShader::SkColorShader(SkReadBuffer& b) : INHERITED(b) {
     // V25_COMPATIBILITY_CODE We had a boolean to make the color shader inherit the paint's
     // color. We don't support that any more.
@@ -266,6 +269,11 @@ SkColorShader::SkColorShader(SkReadBuffer& b) : INHERITED(b) {
     }
     fColor = b.readColor();
 }
+#endif
+
+SkFlattenable* SkColorShader::CreateProc(SkReadBuffer& buffer) {
+    return SkNEW_ARGS(SkColorShader, (buffer.readColor()));
+}
 
 void SkColorShader::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
@@ -383,6 +391,10 @@ void SkColorShader::toString(SkString* str) const {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+SkFlattenable* SkEmptyShader::CreateProc(SkReadBuffer&) {
+    return SkShader::CreateEmptyShader();
+}
+
 #ifndef SK_IGNORE_TO_STRING
 #include "SkEmptyShader.h"