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 {
+    /* 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 {