Adding //aos/vision/debug:debug_framework.

This will allow easy construction of year-specific debug viewers.
Currently supported source types are:
- blobs over tcp
- jpegs from a camera
- blobs from a log
- a random list of jpegs

Change-Id: I1d73f82f98ca5f60b0135ea0dd588759056e0c40
diff --git a/aos/vision/debug/debug_framework.h b/aos/vision/debug/debug_framework.h
new file mode 100644
index 0000000..2f0fcd1
--- /dev/null
+++ b/aos/vision/debug/debug_framework.h
@@ -0,0 +1,85 @@
+#ifndef _AOS_VISION_DEBUG_DEBUG_FRAMEWORK_H_
+#define _AOS_VISION_DEBUG_DEBUG_FRAMEWORK_H_
+
+#include "aos/common/util/global_factory.h"
+#include "aos/vision/blob/range_image.h"
+#include "aos/vision/events/epoll_events.h"
+#include "aos/vision/image/image_types.h"
+
+namespace aos {
+namespace vision {
+
+class BlobStreamViewer;
+
+// Implement per-filter to draw debug viewer information from the filter to
+// the debug BlobStreamViewer.
+class FilterHarness {
+ public:
+  virtual ~FilterHarness() {}
+
+  // Apply the filter-specific thresholding logic.
+  // Blob sources may not have this called at all.
+  virtual RangeImage Threshold(ImagePtr image) = 0;
+
+  // Each filter can only be used by one debug viewer. This will
+  // get called before calling any other methods.
+  virtual void InstallViewer(BlobStreamViewer * /*viewer*/) {}
+
+  // One frame worth of blobs. Returns if the frame is "interesting".
+  virtual bool HandleBlobs(BlobList imgs, ImageFormat fmt) = 0;
+};
+
+// For ImageSource implementations only. Allows registering key press events
+// and installing new blob lists and jpegs.
+class DebugFrameworkInterface {
+ public:
+  virtual ~DebugFrameworkInterface() {}
+
+  void InstallKeyPress(std::function<void(uint32_t)> key_press_event) {
+    key_press_events_.emplace_back(std::move(key_press_event));
+  }
+
+  virtual void NewJpeg(DataRef data) = 0;
+
+  virtual void NewBlobList(BlobList blob_list, ImageFormat fmt) = 0;
+
+  // Expose a EpollLoop to allow waiting for events.
+  virtual aos::events::EpollLoop *Loop() = 0;
+
+ protected:
+  const std::vector<std::function<void(uint32_t)>> &key_press_events() {
+    return key_press_events_;
+  }
+
+ private:
+  std::vector<std::function<void(uint32_t)>> key_press_events_;
+};
+
+// Implemented by each source type. Will stream frames to
+// DebugFrameworkInterface.
+class ImageSource {
+ public:
+  virtual ~ImageSource() {}
+
+  // Printed when you call: debug_viewer help.
+  virtual const char *GetHelpMessage() { return "    No help string :(\n"; }
+
+  // Start streaming frames to DebugFrameworkInterface.
+  virtual void Init(const std::string &args,
+                    DebugFrameworkInterface *interface) = 0;
+};
+
+// Factory for ImageSource.
+SETUP_FACTORY(ImageSource);
+
+#define REGISTER_IMAGE_SOURCE(key, SubClass) \
+  REGISTER_SUBCLASS_BY_KEY(key, ::aos::vision::ImageSource, SubClass)
+
+// Runs loop and never returns.
+// Feeds into a generic filter.
+void DebugFrameworkMain(int argc, char **argv, FilterHarness *filter);
+
+}  // namespace vision
+}  // namespace aos
+
+#endif  // _AOS_VISION_DEBUG_DEBUG_FRAMEWORK_H_