Clean up generatemip.h.

* Move "private" functions into generatemip.inl.
* Use size_t for all dimensions.
* Use uint8_t pointers instead of unsigned char pointers.

BUG=angle:666

Change-Id: I8a1324802e4d670c042e0961c2b6f6fd53f4ebc7
Reviewed-on: https://chromium-review.googlesource.com/202503
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libGLESv2/formatutils.h b/src/libGLESv2/formatutils.h
index 71d212c..3e5d67c 100644
--- a/src/libGLESv2/formatutils.h
+++ b/src/libGLESv2/formatutils.h
@@ -16,9 +16,9 @@
 
 #include <cstddef>
 
-typedef void (*MipGenerationFunction)(unsigned int sourceWidth, unsigned int sourceHeight, unsigned int sourceDepth,
-                                      const unsigned char *sourceData, int sourceRowPitch, int sourceDepthPitch,
-                                      unsigned char *destData, int destRowPitch, int destDepthPitch);
+typedef void (*MipGenerationFunction)(size_t sourceWidth, size_t sourceHeight, size_t sourceDepth,
+                                      const uint8_t *sourceData, size_t sourceRowPitch, size_t sourceDepthPitch,
+                                      uint8_t *destData, size_t destRowPitch, size_t destDepthPitch);
 
 typedef void (*LoadImageFunction)(size_t width, size_t height, size_t depth,
                                   const uint8_t *input, size_t inputRowPitch, size_t inputDepthPitch,