Remove SkCodec::fSrcInfo

This object is now redundant with fEncodedInfo. It holds an
SkColorSpace, which is never used now that SkCodec uses skcms.

SkCodec::getInfo() no longer returns a reference, but creates an
SkImageInfo from the SkEncodedInfo the same way fSrcInfo was
previously created.

Add SkCodec::bounds() and ::dimensions() to replace calling these
methods on getInfo().

Remove srcInfo from SkMaskSwizzler::Create, which just wants to know
whether the src is opaque.

Remove the srcColorType from conversionSupported. Only the base class
version used it. Make it look at fEncodedInfo.color() instead.

Bug: skia:6839
Bug: chromium:887372
Change-Id: I2c0583cae76121211c1a6b49979972fa86daf077
Reviewed-on: https://skia-review.googlesource.com/c/157563
Commit-Queue: Leon Scroggins <scroggo@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
diff --git a/src/codec/SkBmpCodec.cpp b/src/codec/SkBmpCodec.cpp
index cb57f5b..e20e6c9 100644
--- a/src/codec/SkBmpCodec.cpp
+++ b/src/codec/SkBmpCodec.cpp
@@ -605,7 +605,7 @@
     : INHERITED(std::move(info), kXformSrcColorFormat, std::move(stream))
     , fBitsPerPixel(bitsPerPixel)
     , fRowOrder(rowOrder)
-    , fSrcRowBytes(SkAlign4(compute_row_bytes(this->getEncodedInfo().width(), fBitsPerPixel)))
+    , fSrcRowBytes(SkAlign4(compute_row_bytes(this->dimensions().width(), fBitsPerPixel)))
     , fXformBuffer(nullptr)
 {}