Hack together MSAN build.

  - Build our own: freetype.
  - Avoid using: fontconfig, expat, GPU drivers.
  - Lie about safety: libjpeg (only from src/images... need to in src/codec?)

To run:
  $ tools/xsan_build memory dm
  $ out/Debug/dm -v --match ~Codec ~BlurLargeImage ~FontMgrAndroidParser

Notes:
  - Codec triggers issues in piex.
  - BlurLargeImage probably has bugs in the GM only.
  - FontMgrAndroidParser uses expat.

BUG=skia:4550
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1665823002

NOTREECHECKS=true

Review URL: https://codereview.chromium.org/1665823002
diff --git a/src/images/SkImageDecoder_libjpeg.cpp b/src/images/SkImageDecoder_libjpeg.cpp
index 6a032fd..6a3ae87 100644
--- a/src/images/SkImageDecoder_libjpeg.cpp
+++ b/src/images/SkImageDecoder_libjpeg.cpp
@@ -11,6 +11,7 @@
 #include "SkJpegUtility.h"
 #include "SkColorPriv.h"
 #include "SkDither.h"
+#include "SkMSAN.h"
 #include "SkScaledBitmapSampler.h"
 #include "SkStream.h"
 #include "SkTemplates.h"
@@ -524,6 +525,9 @@
             convert_CMYK_to_RGB(srcRow, cinfo.output_width);
         }
 
+        sk_msan_mark_initialized(srcRow, srcRow + cinfo.output_width * srcBytesPerPixel,
+                                 "skbug.com/4550");
+
         sampler.next(srcRow);
         if (bm->height() - 1 == y) {
             // we're done