Don't draw if SkShader::asNewFragmentProcessor fails.

src/gpu/SkGr.cpp

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGr.h"
 
 #include "GrXferProcessor.h"
@@ skipping 624 matching lines @@
         *ctOut = ct;
     }
     if (ptOut) {
         *ptOut = pt;
     }
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void SkPaint2GrPaintNoShader(GrContext* context, GrRenderTarget* rt, const SkPaint& skPaint,
+bool SkPaint2GrPaintNoShader(GrContext* context, GrRenderTarget* rt, const SkPaint& skPaint,
                              GrColor paintColor, bool constantColor, GrPaint* grPaint) {
 
     grPaint->setDither(skPaint.isDither());
     grPaint->setAntiAlias(skPaint.isAntiAlias());
 
     SkXfermode* mode = skPaint.getXfermode();
     GrXPFactory* xpFactory = NULL;
     if (!SkXfermode::AsXPFactory(mode, &xpFactory)) {
         // Fall back to src-over
+        // return false here?
         xpFactory = GrPorterDuffXPFactory::Create(SkXfermode::kSrcOver_Mode);
     }
     SkASSERT(xpFactory);
     grPaint->setXPFactory(xpFactory)->unref();
 
     //set the color of the paint to the one of the parameter
     grPaint->setColor(paintColor);
 
     SkColorFilter* colorFilter = skPaint.getColorFilter();
     if (colorFilter) {
         // if the source color is a constant then apply the filter here once rather than per pixel
         // in a shader.
         if (constantColor) {
             SkColor filtered = colorFilter->filterColor(skPaint.getColor());
             grPaint->setColor(SkColor2GrColor(filtered));
         } else {
             SkTDArray<GrFragmentProcessor*> array;
+            // return false if failed?
             if (colorFilter->asFragmentProcessors(context, &array)) {
                 for (int i = 0; i < array.count(); ++i) {
                     grPaint->addColorProcessor(array[i]);
                     array[i]->unref();
                 }
             }
         }
     }
 
 #ifndef SK_IGNORE_GPU_DITHER
@@ skipping 10 matching lines @@
             // The dither flag is set and the target is likely
             // not going to be dithered by the GPU.
             SkAutoTUnref<GrFragmentProcessor> fp(GrDitherEffect::Create());
             if (fp.get()) {
                 grPaint->addColorProcessor(fp);
                 grPaint->setDither(false);
             }
         }
     }
 #endif
+    return true;
 }
 
-void SkPaint2GrPaintShader(GrContext* context, GrRenderTarget* rt, const SkPaint& skPaint,
-                           const SkMatrix& viewM, bool constantColor, GrPaint* grPaint) {
+bool SkPaint2GrPaint(GrContext* context, GrRenderTarget* rt, const SkPaint& skPaint,
+                     const SkMatrix& viewM, bool constantColor, GrPaint* grPaint) {
     SkShader* shader = skPaint.getShader();
     if (NULL == shader) {
-        SkPaint2GrPaintNoShader(context, rt, skPaint, SkColor2GrColor(skPaint.getColor()),
-                                constantColor, grPaint);
-        return;
+        return SkPaint2GrPaintNoShader(context, rt, skPaint, SkColor2GrColor(skPaint.getColor()),
+                                       constantColor, grPaint);
     }
 
     GrColor paintColor = SkColor2GrColor(skPaint.getColor());
 
     // Start a new block here in order to preserve our context state after calling
     // asFragmentProcessor(). Since these calls get passed back to the client, we don't really
     // want them messing around with the context.
     {
         // Allow the shader to modify paintColor and also create an effect to be installed as
         // the first color effect on the GrPaint.
         GrFragmentProcessor* fp = NULL;
-        if (shader->asFragmentProcessor(context, skPaint, viewM, NULL, &paintColor, &fp) && fp) {
+        if (!shader->asFragmentProcessor(context, skPaint, viewM, NULL, &paintColor, &fp)) {
+            return false;
+        }
+        if (fp) {
             grPaint->addColorProcessor(fp)->unref();
             constantColor = false;
         }
     }
 
     // The grcolor is automatically set when calling asFragmentProcessor.
     // If the shader can be seen as an effect it returns true and adds its effect to the grpaint.
-    SkPaint2GrPaintNoShader(context, rt, skPaint, paintColor, constantColor, grPaint);
+    return SkPaint2GrPaintNoShader(context, rt, skPaint, paintColor, constantColor, grPaint);
 }