faster edge re-sort, drop trailing edges

src/core/SkLineClipper.cpp

Index: src/core/SkLineClipper.cpp
diff --git a/src/core/SkLineClipper.cpp b/src/core/SkLineClipper.cpp
index 1645917d70f5d60ba9722ef2301f12aa6530355d..9d72ea513af26546effb630908285521129a7d72 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;