Reland "SkPDF: Annotations are clipped by canvas clip stack."

Original patch was created by halcanary@google.com, and was reverted
because it triggered crbug.com/503541.

This patch fixes a bug in the original patch about clip path
transformation.

> Also, remove some SkPDFDevice functions.
> Will fix this GM: http://crrev.com/1159273003
> BUG=skia:3872
> Review URL: https://codereview.chromium.org/1148263005

BUG=skia:3872
BUG=503514

Review URL: https://codereview.chromium.org/1238503007
diff --git a/gm/annotated_text.cpp b/gm/annotated_text.cpp
index ab7e816..7126206 100644
--- a/gm/annotated_text.cpp
+++ b/gm/annotated_text.cpp
@@ -27,7 +27,7 @@
 DEF_SIMPLE_GM(annotated_text, canvas, 512, 512) {
     SkAutoCanvasRestore autoCanvasRestore(canvas, true);
     canvas->clear(SK_ColorWHITE);
-    canvas->clipRect(SkRect::MakeXYWH(64, 64, 384, 384));
+    canvas->clipRect(SkRect::MakeXYWH(64, 64, 256, 256));
     canvas->clear(0xFFEEEEEE);
     SkPaint p;
     p.setTextSize(40);