DM: write failed comparison mode .pngs one more level deep in the tree.

dm/DMTask.cpp

 #include "DMTask.h"
 
 #include "DMTaskRunner.h"
 #include "DMUtil.h"
 #include "SkBitmap.h"
 #include "SkCommandLineFlags.h"
 
 namespace DM {
 
 Task::Task(Reporter* reporter, TaskRunner* taskRunner)
-    : fReporter(reporter), fTaskRunner(taskRunner) {
+    : fReporter(reporter), fTaskRunner(taskRunner), fDepth(0) {
     fReporter->start();
 }
 
-Task::Task(const Task& that)
-    : INHERITED(that)
-    , fReporter(that.fReporter)
-    , fTaskRunner(that.fTaskRunner) {
+Task::Task(const Task& parent)
+    : INHERITED(parent)
+    , fReporter(parent.fReporter)
+    , fTaskRunner(parent.fTaskRunner)
+    , fDepth(parent.depth()+1) {
     fReporter->start();
 }
 
 Task::~Task() {}
 
 void Task::run() {
     if (!this->shouldSkip()) {
         this->draw();
     }
     fReporter->finish();
     fReporter->updateStatusLine();
     delete this;
 }
 
 void Task::spawnChild(Task* task) {
     if (!task->usesGpu()) {
         fTaskRunner->add(task);
     } else {
         SkDEBUGFAIL("Sorry, we can't spawn GPU tasks. :(  See comment in TaskRunner::wait().");
     }
 }
 
 void Task::fail() {
     fReporter->fail(this->name());
 }
 
 }  // namespace DM