Add abilitly to query audit trail for batches by draw op

tools/skiaserve/Request.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 "Request.h"
 
 #include "png.h"
@@ skipping 120 matching lines @@
             fGPUEnabled = true;
             return true;
         }
         return false;
     }
     fSurface.reset(this->createCPUSurface());
     fGPUEnabled = false;
     return true;
 }
 
+GrAuditTrail* Request::getAuditTrail(SkCanvas* canvas) {
+    GrAuditTrail* at = nullptr;
+#if SK_SUPPORT_GPU
+    GrRenderTarget* rt = canvas->internal_private_accessTopLayerRenderTarget();
+    if (rt) {
+        GrContext* ctx = rt->getContext();
+        if (ctx) {
+            at = ctx->getAuditTrail();
+        }
+    }
+#endif
+    return at;
+}
+
+void Request::cleanupAuditTrail(SkCanvas* canvas) {
+    GrAuditTrail* at = this->getAuditTrail(canvas);
+    if (at) {
+        GrAuditTrail::AutoEnable ae(at);
+        at->fullReset();
+    }
+}
+
 SkData* Request::getJsonOps(int n) {
     SkCanvas* canvas = this->getCanvas();
     Json::Value root = fDebugCanvas->toJSON(fUrlDataManager, n, canvas);
     root["mode"] = Json::Value(fGPUEnabled ? "gpu" : "cpu");
     SkDynamicMemoryWStream stream;
     stream.writeText(Json::FastWriter().write(root).c_str());
 
+    this->cleanupAuditTrail(canvas);
+
     return stream.copyToData();
 }
 
 SkData* Request::getJsonBatchList(int n) {
     SkCanvas* canvas = this->getCanvas();
     SkASSERT(fGPUEnabled);
 
     // TODO if this is inefficient we could add a method to GrAuditTrail which takes
     // a Json::Value and is only compiled in this file
     Json::Value parsedFromString;
 #if SK_SUPPORT_GPU
-    GrRenderTarget* rt = canvas->internal_private_accessTopLayerRenderTarget();
-    SkASSERT(rt);
-    GrContext* ctx = rt->getContext();
-    SkASSERT(ctx);
-    GrAuditTrail* at = ctx->getAuditTrail();
+    GrAuditTrail* at = this->getAuditTrail(canvas);
     GrAuditTrail::AutoManageBatchList enable(at);
     
     fDebugCanvas->drawTo(canvas, n);
 
     Json::Reader reader;
     SkDEBUGCODE(bool parsingSuccessful = )reader.parse(at->toJson(true).c_str(),
                                                        parsedFromString);
     SkASSERT(parsingSuccessful);
 #endif
 
@@ skipping 16 matching lines @@
     SkIRect clip = fDebugCanvas->getCurrentClip();
     Json::Value info(Json::objectValue);
     info["ViewMatrix"] = SkJSONCanvas::MakeMatrix(vm);
     info["ClipRect"] = SkJSONCanvas::MakeIRect(clip);
 
     std::string json = Json::FastWriter().write(info);
 
     // We don't want the null terminator so strlen is correct
     return SkData::NewWithCopy(json.c_str(), strlen(json.c_str()));
 }