Extend SkImageGenerator to support natively generated GrTextures

include/core/SkImageInfo.h

Index: include/core/SkImageInfo.h
diff --git a/include/core/SkImageInfo.h b/include/core/SkImageInfo.h
index 459a0ee43ef0001530a0bff6f36d9b670dfbee7e..7b48c3a43007911b45dd34aad666ef5eba3ec44e 100644
--- a/include/core/SkImageInfo.h
+++ b/include/core/SkImageInfo.h
@@ -16,6 +16,22 @@ class SkReadBuffer;
 class SkWriteBuffer;
 
 /**
+ *  This enum provides information about "how" an image will be used. For older GPUs that do not
+ *  support non-power-of-2 tiling, some routines need to know this information before they create
+ *  a texture.
+ */
+enum SkImageUsageType {

[scroggo, 2015/08/13 19:59:13]

Maybe this name should incorporate the word "tiling" somehow, since it only
applies to tiling?

It also seems like it only relates to drawing via the GPU? Does it belong here?
Maybe in some GPU specific file? (I guess you want to still be able to reference
it even when SK_SUPPORT_GPU is false?)

[reed1, 2015/08/13 20:57:08]

It also appears in SkImageGenrerator.h which is public, so I think it has to be
public and not necessarily gpu-specific. I'm fine to change the name later.

+    /* Image will not be tiled (regardless of filtering) */
+    kUntiled_SkImageUsageType,
+
+    /* Image will be tiled, but not filtered */
+    kTiled_Unfiltered_SkImageUsageType,
+
+    /* Image will be tiled and filtered */
+    kTiled_Filtered_SkImageUsageType,
+};
+
+/**
  *  Describes how to interpret the alpha compoent of a pixel.
  */
 enum SkAlphaType {