Safely handle unsupported color xforms in SkCodec

(1) The transformation code *should* support any src SkColorSpace
that we successfully parse.  This is agreed upon internally and
by clients.  The fact that we currently don't is just a bug...
(2) We cannot and will not support all SkColorSpaces as dsts.

So if we fail to make a SkColorSpaceXform, we should assume that
it was caused by a bad dst color space.  The correct response in
this case is to return kInvalidConversion.  I've rewritten the CL
to do this.

The fact that weird src spaces will sometimes trigger a
kInvalidConversion is just a bug that is being actively worked on.

TBR=reed@google.com

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3661

Change-Id: Iac2b45120507ec71b1b3d555c61931f7348dad9e
Reviewed-on: https://skia-review.googlesource.com/3661
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Reviewed-by: Robert Aftias <raftias@google.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/src/codec/SkCodec.cpp b/src/codec/SkCodec.cpp
index 84afc2bdee..b6ce65e7b2 100644
--- a/src/codec/SkCodec.cpp
+++ b/src/codec/SkCodec.cpp
@@ -9,6 +9,7 @@
 #include "SkCodec.h"
 #include "SkCodecPriv.h"
 #include "SkColorSpace.h"
+#include "SkColorSpaceXform.h"
 #include "SkData.h"
 #include "SkGifCodec.h"
 #include "SkHalf.h"
@@ -483,3 +484,15 @@ void SkCodec::fillIncompleteImage(const SkImageInfo& info, void* dst, size_t row
         }
     }
 }
+
+bool SkCodec::initializeColorXform(const SkImageInfo& dstInfo) {
+    fColorXform = nullptr;
+    if (needs_color_xform(dstInfo, fSrcInfo)) {
+        fColorXform = SkColorSpaceXform::New(fSrcInfo.colorSpace(), dstInfo.colorSpace());
+        if (!fColorXform) {
+            return false;
+        }
+    }
+
+    return true;
+}