Cycles: Initial implementation of detailed statistics

Gathers information about object geometry and textures. Very basic at
this moment, but need to start somewhere.

Things which needs to be included still:

- "Runtime" information, like BVH. While it is not directly controllable
  by artists, it's still important to know.

- Device array sizes. Again, not under artists control, but is added to
  the overall size.

- Memory peak at different synchronization stages.

At this point it simply prints info to the stdout after F12 is done,
need better control over that too.

Reviewers: brecht

Differential Revision: https://developer.blender.org/D3566

intern/cycles/render/image.cpp

@@ -17,6 +17,7 @@
 #include "device/device.h"
 #include "render/image.h"
 #include "render/scene.h"
+#include "render/stats.h"
 
 #include "util/util_foreach.h"
 #include "util/util_logging.h"
@@ -1042,4 +1043,15 @@ void ImageManager::device_free(Device *device)
 	}
 }
 
+void ImageManager::collect_statistics(RenderStats *stats)
+{
+	for(int type = 0; type < IMAGE_DATA_NUM_TYPES; type++) {
+		foreach(const Image *image, images[type]) {
+			stats->image.textures.add_entry(
+			        NamedSizeEntry(path_filename(image->filename),
+			                       image->mem->memory_size()));
+		}
+	}
+}
+
 CCL_NAMESPACE_END