Clean up quick rejection, especially surrounding points + lines.

bug:4351353

quickReject and quickRejectNoScissor have been renamed and refactored:
- to make the scissor side effect clear and explicit
- dangerous methods no longer public
- to make the simple quick reject check logic const
- simple quick reject is now conservative

This CL also fixes several issues with line and point quickRejection -
sub-pixel and hairline lines are much less likely to be incorrectly
rejected, especially at small canvas scale.

Additionally, alpha modulation for AA points < 1px in size is now
correct, dumplicating SW behavior (similar to lines and stroked
shapes work).

Change-Id: Ibb0710c721b9fb415d05acf54dd3d2b4d602156a
diff --git a/libs/hwui/PathTessellator.h b/libs/hwui/PathTessellator.h
index 85797fc..e0044e8 100644
--- a/libs/hwui/PathTessellator.h
+++ b/libs/hwui/PathTessellator.h
@@ -102,7 +102,7 @@
 
 class PathTessellator {
 public:
-    static void expandBoundsForStroke(SkRect& bounds, const SkPaint* paint, bool forceExpand);
+    static void expandBoundsForStroke(SkRect& bounds, const SkPaint* paint);
 
     static void tessellatePath(const SkPath& path, const SkPaint* paint,
             const mat4 *transform, VertexBuffer& vertexBuffer);