Remove SkShader virtual method validContext

patch from issue 267923005

BUG=skia:
R=scroggo@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/261773005

git-svn-id: http://skia.googlecode.com/svn/trunk@14573 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkFilterShader.h b/src/core/SkFilterShader.h
index 629f3f8..3f983e2 100644
--- a/src/core/SkFilterShader.h
+++ b/src/core/SkFilterShader.h
@@ -17,8 +17,6 @@
     SkFilterShader(SkShader* shader, SkColorFilter* filter);
     virtual ~SkFilterShader();
 
-    virtual bool validContext(const ContextRec&, SkMatrix* totalInverse) const SK_OVERRIDE;
-    virtual SkShader::Context* createContext(const ContextRec&, void* storage) const SK_OVERRIDE;
     virtual size_t contextSize() const SK_OVERRIDE;
 
     class FilterShaderContext : public SkShader::Context {
@@ -44,6 +42,8 @@
 protected:
     SkFilterShader(SkReadBuffer& );
     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
+    virtual Context* onCreateContext(const ContextRec&, void* storage) const SK_OVERRIDE;
+    
 
 private:
     SkShader*       fShader;