faster edge re-sort, drop trailing edges

1. drop edges that are wholly on the right (in the non-convex walker)
2. scan and swap once, instead of swapping as we go during re-sort

BUG=skia:

Review URL: https://codereview.chromium.org/891613003

1 files changed, 4 insertions, 1 deletions

diff --git a/src/core/SkLineClipper.cpp b/src/core/SkLineClipper.cpp
index 1645917d70..9d72ea513a 100644
--- a/src/core/SkLineClipper.cpp
+++ b/src/core/SkLineClipper.cpp
@@ -173,7 +173,7 @@ static void sect_with_horizontal_test_for_pin_results() {
 #endif
 
 int SkLineClipper::ClipLine(const SkPoint pts[], const SkRect& clip,
-                            SkPoint lines[]) {
+                            SkPoint lines[], bool canClipToTheRight) {
 #ifdef SK_DEBUG
     {
         static bool gOnce;
@@ -241,6 +241,9 @@ int SkLineClipper::ClipLine(const SkPoint pts[], const SkRect& clip,
         result = tmp;
         reverse = false;
     } else if (tmp[index0].fX >= clip.fRight) {    // wholly to the right
+        if (canClipToTheRight) {
+            return 0;
+        }
         tmp[0].fX = tmp[1].fX = clip.fRight;
         result = tmp;
         reverse = false;