remove unused "swap" stage

Change-Id: I25619f010f8ac6441529cfe8dff2d8c42d7400cf
Reviewed-on: https://skia-review.googlesource.com/20988
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>

src/core/SkRasterPipeline.h

@@ -61,7 +61,7 @@ struct SkJumper_constants;
 
 #define SK_RASTER_PIPELINE_STAGES(M)                             \
     M(callback)                                                  \
-    M(move_src_dst) M(move_dst_src) M(swap)                      \
+    M(move_src_dst) M(move_dst_src)                              \
     M(clamp_0) M(clamp_1) M(clamp_a) M(clamp_a_dst)              \
     M(unpremul) M(premul)                                        \
     M(set_rgb) M(swap_rb) M(swap_rb_dst)                         \

src/jumper/SkJumper.cpp

@@ -83,7 +83,6 @@ using StartPipelineFn = void(size_t,size_t,size_t,void**,K*);
     M(lerp_u8)           \
     M(scale_1_float)     \
     M(scale_u8)          \
-    M(swap)              \
     M(move_src_dst)      \
     M(move_dst_src)      \
     M(clear)             \

src/jumper/SkJumper_stages.cpp

@@ -526,17 +526,6 @@ STAGE(swap_rb_dst) {
     db = tmp;
 }
 
-STAGE(swap) {
-    auto swap = [](F& v, F& dv) {
-        auto tmp = v;
-        v = dv;
-        dv = tmp;
-    };
-    swap(r, dr);
-    swap(g, dg);
-    swap(b, db);
-    swap(a, da);
-}
 STAGE(move_src_dst) {
     dr = r;
     dg = g;

src/jumper/SkJumper_stages_lowp.cpp

@@ -340,17 +340,6 @@ STAGE(swap_rb_dst) {
     db = tmp;
 }
 
-STAGE(swap) {
-    auto swap = [](F& v, F& dv) {
-        auto tmp = v;
-        v = dv;
-        dv = tmp;
-    };
-    swap(r, dr);
-    swap(g, dg);
-    swap(b, db);
-    swap(a, da);
-}
 STAGE(move_src_dst) {
     dr = r;
     dg = g;

tests/SkRasterPipelineTest.cpp

@@ -21,10 +21,8 @@ DEF_TEST(SkRasterPipeline, r) {
     void* store_ctx  = &result;
 
     SkRasterPipeline_<256> p;
-    p.append(SkRasterPipeline::load_f16, &load_s_ctx);
-    p.append(SkRasterPipeline::move_src_dst);
-    p.append(SkRasterPipeline::load_f16, &load_d_ctx);
-    p.append(SkRasterPipeline::swap);
+    p.append(SkRasterPipeline::load_f16,     &load_s_ctx);
+    p.append(SkRasterPipeline::load_f16_dst, &load_d_ctx);
     p.append(SkRasterPipeline::srcover);
     p.append(SkRasterPipeline::store_f16, &store_ctx);
     p.run(0,0,1);