Add image decoding mode to DM.

dm/DMImageTask.h

+#ifndef DMImageTask_DEFINED
+#define DMImageTask_DEFINED
+
+#include "DMReporter.h"
+#include "DMTask.h"
+#include "DMTaskRunner.h"
+#include "SkPicture.h"
+#include "SkString.h"
+#include "SkTemplates.h"
+
+// Decode an image into its natural bitmap, perhaps decoding random subsets.
+
+namespace DM {
+
+class ImageTask : public CpuTask {
+public:
+    ImageTask(Reporter*, TaskRunner*, const SkData*, SkString name, int subsets = 0);
+
+    void draw() SK_OVERRIDE;
+    bool shouldSkip() const SK_OVERRIDE { return false; }
+    SkString name() const SK_OVERRIDE { return fName; }
+
+private:
+    SkAutoTUnref<const SkData> fEncoded;
+    const SkString fName;
+    int fSubsets;
+};
+
+}  // namespace DM
+
+#endif // DMImageTask_DEFINED