remove unneeded SkShader::validContext

src/core/SkBlitter.cpp

Index: src/core/SkBlitter.cpp
diff --git a/src/core/SkBlitter.cpp b/src/core/SkBlitter.cpp
index 74cd29824e1bf4f08b4b4701da2efea9862a1a44..2f3cdef6e3f9b70c1a0d42a364f1c9d19d61f258 100644
--- a/src/core/SkBlitter.cpp
+++ b/src/core/SkBlitter.cpp
@@ -591,29 +591,14 @@ public:
         return size;
     }
 
-    virtual bool validContext(const ContextRec& rec, SkMatrix* totalInverse) const SK_OVERRIDE {
-        if (!this->INHERITED::validContext(rec, totalInverse)) {
-            return false;
-        }
-        if (fProxy) {
-            return fProxy->validContext(rec);
-        }
-        return true;
-    }
-
-    virtual SkShader::Context* createContext(const ContextRec& rec, void* storage) const SK_OVERRIDE
-    {
-        if (!this->validContext(rec, NULL)) {
-            return NULL;
-        }
-
-        SkShader::Context* proxyContext;
+    virtual Context* onCreateContext(const ContextRec& rec, void* storage) const SK_OVERRIDE {
+        SkShader::Context* proxyContext = NULL;
         if (fProxy) {
             char* proxyContextStorage = (char*) storage + sizeof(Sk3DShaderContext);
             proxyContext = fProxy->createContext(rec, proxyContextStorage);
-            SkASSERT(proxyContext);
-        } else {
-            proxyContext = NULL;
+            if (!proxyContext) {
+                return NULL;
+            }
         }
         return SkNEW_PLACEMENT_ARGS(storage, Sk3DShaderContext, (*this, rec, proxyContext));
     }
@@ -1035,9 +1020,6 @@ SkShaderBlitter::~SkShaderBlitter() {
 bool SkShaderBlitter::resetShaderContext(const SkBitmap& device, const SkPaint& paint,
                                          const SkMatrix& matrix) {
     SkShader::ContextRec rec(device, paint, matrix);
-    if (!fShader->validContext(rec)) {
-        return false;
-    }
 
     // Only destroy the old context if we have a new one. We need to ensure to have a
     // live context in fShaderContext because the storage is owned by an SkSmallAllocator
@@ -1046,7 +1028,5 @@ bool SkShaderBlitter::resetShaderContext(const SkBitmap& device, const SkPaint&
     // shader to create it. It is therefore safe to re-use the storage.
     fShaderContext->~Context();
     fShaderContext = fShader->createContext(rec, (void*)fShaderContext);
-    SkASSERT(fShaderContext);
-
-    return true;
+    return fShaderContext != NULL;
 }