reset shader compilations for stats

BUG=skia:

Review URL: https://codereview.chromium.org/1491823003

bench/SKPBench.cpp

@@ -157,6 +157,7 @@ void SKPBench::drawPicture() {
 }
 
 #if SK_SUPPORT_GPU
+#include "GrGpu.h"
 static void draw_pic_for_stats(SkCanvas* canvas, GrContext* context, const SkPicture* picture,
                                SkTArray<SkString>* keys, SkTArray<double>* values,
                                const char* tag) {
@@ -186,6 +187,7 @@ void SKPBench::getGpuStats(SkCanvas* canvas, SkTArray<SkString>* keys, SkTArray<
     context->flush();
     context->freeGpuResources();
     context->resetContext();
+    context->getGpu()->resetShaderCacheForTesting();
     draw_pic_for_stats(canvas, context, fPic, keys, values, "first_frame");
 
     // draw second frame

src/gpu/GrGpu.h

@@ -414,6 +414,9 @@ public:
     // This is only to be used in GL-specific tests.
     virtual const GrGLContext* glContextForTesting() const { return nullptr; }
 
+    // This is only to be used by testing code
+    virtual void resetShaderCacheForTesting() const {}
+
 protected:
     // Functions used to map clip-respecting stencil tests into normal
     // stencil funcs supported by GPUs.

src/gpu/gl/GrGLGpu.cpp

@@ -3384,6 +3384,10 @@ void GrGLGpu::deleteTestingOnlyBackendTexture(GrBackendObject id, bool abandonTe
 #endif
 }
 
+void GrGLGpu::resetShaderCacheForTesting() const {
+    fProgramCache->abandon();
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 GrGLAttribArrayState* GrGLGpu::HWGeometryState::bindArrayAndBuffersToDraw(
                                                 GrGLGpu* gpu,

src/gpu/gl/GrGLGpu.h

@@ -129,6 +129,8 @@ public:
     bool isTestingOnlyBackendTexture(GrBackendObject) const override;
     void deleteTestingOnlyBackendTexture(GrBackendObject, bool abandonTexture) const override;
 
+    void resetShaderCacheForTesting() const override;
+
 private:
     GrGLGpu(GrGLContext* ctx, GrContext* context);
 
@@ -215,6 +217,7 @@ private:
         ProgramCache(GrGLGpu* gpu);
         ~ProgramCache();
 
+        void reset();
         void abandon();
         GrGLProgram* refProgram(const DrawArgs&);
 

src/gpu/gl/GrGLGpuProgramCache.cpp

@@ -77,13 +77,30 @@ GrGLGpu::ProgramCache::~ProgramCache() {
 #endif
 }
 
-void GrGLGpu::ProgramCache::abandon() {
+void GrGLGpu::ProgramCache::reset() {
     for (int i = 0; i < fCount; ++i) {
         SkASSERT(fEntries[i]->fProgram.get());
         fEntries[i]->fProgram->abandon();
         delete fEntries[i];
+        fEntries[i] = nullptr;
     }
     fCount = 0;
+
+    // zero out hash table
+    for (int i = 0; i < 1 << kHashBits; i++) {
+        fHashTable[i] = nullptr;
+    }
+
+    fCurrLRUStamp = 0;
+#ifdef PROGRAM_CACHE_STATS
+    fTotalRequests = 0;
+    fCacheMisses = 0;
+    fHashMisses = 0;
+#endif
+}
+
+void GrGLGpu::ProgramCache::abandon() {
+    this->reset();
 }
 
 int GrGLGpu::ProgramCache::search(const GrProgramDesc& desc) const {