Fix clipping when all analytic FP creations can be skipped

src/gpu/GrClipMaskManager.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrClipMaskManager.h"
 #include "GrCaps.h"
 #include "GrDrawContext.h"
@@ skipping 90 matching lines @@
             element->asPath(&path);
             if (path_needs_SW_renderer(this->getContext(), fDrawTarget, pipelineBuilder, translate,
                                        path, stroke, element->isAA())) {
                 return true;
             }
         }
     }
     return false;
 }
 
-const GrFragmentProcessor* GrClipMaskManager::getAnalyticClipProcessor(
-                                                        const GrReducedClip::ElementList& elements,
-                                                        const SkVector& clipToRTOffset,
-                                                        const SkRect* drawBounds) {
+bool GrClipMaskManager::getAnalyticClipProcessor(const GrReducedClip::ElementList& elements,
+                                                 SkVector& clipToRTOffset,
+                                                 const SkRect* drawBounds,
+                                                 const GrFragmentProcessor** resultFP) {
     SkRect boundsInClipSpace;
     if (drawBounds) {
         boundsInClipSpace = *drawBounds;
         boundsInClipSpace.offset(-clipToRTOffset.fX, -clipToRTOffset.fY);
     }
     SkASSERT(elements.count() <= kMaxAnalyticElements);
     const GrFragmentProcessor* fps[kMaxAnalyticElements];
     for (int i = 0; i < kMaxAnalyticElements; ++i) {
         fps[i] = nullptr;
     }
@@ skipping 58 matching lines @@
             }
             if (!fps[fpCnt]) {
                 failed = true;
                 break;
             }
             fpCnt++;
         }
         iter.next();
     }
 
-    const GrFragmentProcessor* resultFP = nullptr;
-    if (!failed) {
-        resultFP = GrFragmentProcessor::RunInSeries(fps, fpCnt);
+    *resultFP = nullptr;
+    if (!failed && fpCnt) {
+        *resultFP = GrFragmentProcessor::RunInSeries(fps, fpCnt);
     }
     for (int i = 0; i < fpCnt; ++i) {
         fps[i]->unref();
     }
-    return resultFP;
+    return !failed;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // sort out what kind of clip mask needs to be created: alpha, stencil,
 // scissor, or entirely software
 bool GrClipMaskManager::setupClipping(const GrPipelineBuilder& pipelineBuilder,
                                       GrPipelineBuilder::AutoRestoreStencil* ars,
                                       GrScissorState* scissorState,
                                       const SkRect* devBounds,
                                       GrAppliedClip* out) {
@@ skipping 65 matching lines @@
     // longer shaders.
     if (elements.count() <= kMaxAnalyticElements) {
         SkVector clipToRTOffset = { SkIntToScalar(-clip.origin().fX),
                                     SkIntToScalar(-clip.origin().fY) };
         // When there are multiple color samples we want to do per-sample clipping, not compute
         // a fractional pixel coverage.
         bool disallowAnalyticAA = pipelineBuilder.getRenderTarget()->isUnifiedMultisampled();
         const GrFragmentProcessor* clipFP = nullptr;
         if (elements.isEmpty() ||
             (requiresAA && !disallowAnalyticAA &&
-             SkToBool(clipFP = this->getAnalyticClipProcessor(elements, clipToRTOffset, devBounds)))) {
+             this->getAnalyticClipProcessor(elements, clipToRTOffset, devBounds, &clipFP))) {
             SkIRect scissorSpaceIBounds(clipSpaceIBounds);
             scissorSpaceIBounds.offset(-clip.origin());
             if (nullptr == devBounds ||
                 !SkRect::Make(scissorSpaceIBounds).contains(*devBounds)) {
                 scissorState->set(scissorSpaceIBounds);
             }
             this->setPipelineBuilderStencil(pipelineBuilder, ars);
             out->fClipCoverageFP.reset(clipFP);
             return true;
         }
@@ skipping 814 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 
 void GrClipMaskManager::adjustPathStencilParams(const GrStencilAttachment* stencilAttachment,
                                                 GrStencilSettings* settings) {
     if (stencilAttachment) {
         int stencilBits = stencilAttachment->bits();
         this->adjustStencilParams(settings, fClipMode, stencilBits);
     }
 }