Make LinearSrcOverBench not crash in constructor when resource path is missing

bench/SkBlend_optsBench.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <tuple>
 
 #include "Benchmark.h"
@@ skipping 75 matching lines @@
     static void BlendN(uint32_t* dst, int count, const uint32_t* src) {
         sk_sse41::srcover_srgb_srgb(dst, src, count, count);
     }
 };
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 template <typename Blender>
 class LinearSrcOverBench : public Benchmark {
 public:
-    LinearSrcOverBench(const char* fileName) {
+    LinearSrcOverBench(const char* fileName) : fFileName(fileName) {
         fName = "LinearSrcOver";
         fName.append(fileName);
         fName.append(Blender::Name());
-
-        sk_sp<SkImage> image = GetResourceAsImage(fileName);
-        SkBitmap bm;
-        if (!as_IB(image)->getROPixels(&bm)) {
-            SkFAIL("Could not read resource");
-        }
-        bm.peekPixels(&fPixmap);
-        fCount = fPixmap.rowBytesAsPixels();
-        fDst.reset(fCount);
-        memset(fDst.get(), 0, fPixmap.rowBytes());
     }
 
 protected:
     bool isSuitableFor(Backend backend) override {
         return backend == kNonRendering_Backend && Blender::WorksOnCpu();
     }
     const char* onGetName() override { return fName.c_str(); }
+
+    void onPreDraw(SkCanvas*) override {
+        if (!fPixmap.addr()) {
+            sk_sp<SkImage> image = GetResourceAsImage(fFileName.c_str());
+            SkBitmap bm;
+            if (!as_IB(image)->getROPixels(&bm)) {
+                SkFAIL("Could not read resource");
+            }
+            bm.peekPixels(&fPixmap);
+            fCount = fPixmap.rowBytesAsPixels();
+            fDst.reset(fCount);
+            memset(fDst.get(), 0, fPixmap.rowBytes());
+        }
+    }
+
     void onDraw(int loops, SkCanvas*) override {
         SkASSERT(fPixmap.colorType() == kN32_SkColorType);
 
         const int width = fPixmap.rowBytesAsPixels();
 
         for (int i = 0; i < loops * INNER_LOOPS; ++i) {
             const uint32_t* src = fPixmap.addr32();
             for (int y = 0; y < fPixmap.height(); y++) {
                 Blender::BlendN(fDst.get(), width, src);
                 src += width;
             }
         }
     }
 
     void onPostDraw(SkCanvas*) override {
         // Make sure the compiler does not optimize away the operation.
         volatile uint32_t v = 0;
         for (int i = 0; i < fCount; i++) {
             v ^= fDst[i];
         }
     }
 
 private:
     int fCount;
     SkAutoTArray<uint32_t> fDst;
+    SkString fFileName;
     SkString fName;
     SkPixmap fPixmap;
 
     typedef Benchmark INHERITED;
 };
 
 #if defined(SK_CPU_X86) && !defined(SK_BUILD_FOR_IOS)
 #define BENCHES(fileName)                                                        \
 DEF_BENCH( return new LinearSrcOverBench<SrcOverVSkOptsBruteForce>(fileName); )  \
 DEF_BENCH( return new LinearSrcOverBench<SrcOverVSkOptsTrivial>(fileName); )     \
 DEF_BENCH( return new LinearSrcOverBench<SrcOverVSkOptsNonSimdCore>(fileName); ) \
 DEF_BENCH( return new LinearSrcOverBench<SrcOverVSkOptsDefault>(fileName); )     \
 DEF_BENCH( return new LinearSrcOverBench<SrcOverVSkOptsSSE41>(fileName); )
 #else
 #define BENCHES(fileName)                                                        \
 DEF_BENCH( return new LinearSrcOverBench<SrcOverVSkOptsBruteForce>(fileName); )  \
 DEF_BENCH( return new LinearSrcOverBench<SrcOverVSkOptsTrivial>(fileName); )     \
 DEF_BENCH( return new LinearSrcOverBench<SrcOverVSkOptsNonSimdCore>(fileName); ) \
 DEF_BENCH( return new LinearSrcOverBench<SrcOverVSkOptsDefault>(fileName); )
 #endif
 
 BENCHES("yellow_rose.png")
 BENCHES("baby_tux.png")
 BENCHES("plane.png")
 BENCHES("mandrill_512.png")
 BENCHES("iconstrip.png")