Remove unnecessary getColorSpace() API from SkCodec

Not needed since now we can get it from the SkImageInfo.

TBR=reed@google.com
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2170793004

Review-Url: https://codereview.chromium.org/2170793004
diff --git a/tests/ColorSpaceTest.cpp b/tests/ColorSpaceTest.cpp
index 442ed3d..df03ea4 100644
--- a/tests/ColorSpaceTest.cpp
+++ b/tests/ColorSpaceTest.cpp
@@ -65,7 +65,7 @@
     REPORTER_ASSERT(r, nullptr != codec);
 
 #if (PNG_LIBPNG_VER_MAJOR > 1) || (PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR >= 6)
-    SkColorSpace* colorSpace = codec->getColorSpace();
+    SkColorSpace* colorSpace = codec->getInfo().colorSpace();
     REPORTER_ASSERT(r, nullptr != colorSpace);
 
     test_space(r, colorSpace, &g_sRGB_XYZ[0], &g_sRGB_XYZ[3], &g_sRGB_XYZ[6],
@@ -86,7 +86,7 @@
         return;
     }
 
-    SkColorSpace* colorSpace = codec->getColorSpace();
+    SkColorSpace* colorSpace = codec->getInfo().colorSpace();
     REPORTER_ASSERT(r, nullptr != colorSpace);
 
     const float red[] = { 0.385117f, 0.716904f, 0.0970612f };