Simplify subset computation in SkGifImageReader

If xOffset or yOffset was not zero, these computations would not
be evaluated anyway, so no need to add zero for these comparisons.

(Split off from CL 9810)

Change-Id: I8481eb257d96766696945cef4eafaff4281fb7d9
Reviewed-on: https://skia-review.googlesource.com/11782
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>

diff --git a/third_party/gif/SkGifImageReader.cpp b/third_party/gif/SkGifImageReader.cpp
index f617ccd..f8a454a 100644 (file)
--- a/third_party/gif/SkGifImageReader.cpp
+++ b/third_party/gif/SkGifImageReader.cpp
@@ -760,8 +760,8 @@ bool SkGifImageReader::parse(SkGifImageReader::SkGIFParseQuery query)
                     m_firstFrameSupportsIndex8 = true;
                 } else {
                     const bool frameIsSubset = xOffset > 0 || yOffset > 0
-                            || xOffset + width < m_screenWidth
-                            || yOffset + height < m_screenHeight;
+                            || width < m_screenWidth
+                            || height < m_screenHeight;
                     m_firstFrameHasAlpha = frameIsSubset;
                     m_firstFrameSupportsIndex8 = !frameIsSubset;
                 }