DM: add --writePath

dm/DMWriteTask.h

+#ifndef DMWriteTask_DEFINED
+#define DMWriteTask_DEFINED
+
+#include "DMTask.h"
+#include "SkBitmap.h"
+#include "SkString.h"
+
+// Writes a bitmap to a file.
+
+namespace DM {
+
+class WriteTask : public Task {
+
+public:
+    WriteTask(const Task& parent, SkBitmap bitmap);
+
+    virtual void draw() SK_OVERRIDE;
+    virtual bool usesGpu() const SK_OVERRIDE { return false; }
+    virtual bool shouldSkip() const SK_OVERRIDE;
+    virtual SkString name() const SK_OVERRIDE;
+
+private:
+    SkString fConfig;
+    SkString fGmName;
+    const SkBitmap fBitmap;
+};
+
+}  // namespace DM
+
+#endif  // DMWriteTask_DEFINED