non-linear blending first steps

Code:
  - Add a non-linear blending bit and makeNonlinearBlending()
    to SkColorSpace
  - remove enough F16=linear checks to make it possible to
    create surfaces and encode pngs with nonlinear F16

Testing:
  - add "esrgb" software config to DM, run it
  - add "srgbnl" software config, run it
  - deemphasize importance of "srgb" config on bots
  - update unit tests to reflect relaxed F16 constraints
  - add a new unit test file with _really_ basic tests,
    and a new unit test that's not working yet

Bug: skia:7942

Change-Id: I8ac042bdf9f3d791765393b68fd9256375184d83
Reviewed-on: https://skia-review.googlesource.com/127325
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>

2 files changed, 3 insertions, 5 deletions

diff --git a/include/core/SkColorSpace.h b/include/core/SkColorSpace.h
index 2bc297efe0..801ccf2098 100644
--- a/include/core/SkColorSpace.h
+++ b/include/core/SkColorSpace.h
@@ -259,6 +259,9 @@ public:
      */
     const SkData* profileData() const { return this->onProfileData(); }
 
+    virtual bool nonlinearBlending() const { return false; }
+    virtual sk_sp<SkColorSpace> makeNonlinearBlending() const { return nullptr; }
+
 private:
     virtual const SkMatrix44* onToXYZD50() const = 0;
     virtual uint32_t onToXYZD50Hash() const = 0;
diff --git a/include/private/SkImageInfoPriv.h b/include/private/SkImageInfoPriv.h
index 597906af29..aac1750708 100644
--- a/include/private/SkImageInfoPriv.h
+++ b/include/private/SkImageInfoPriv.h
@@ -115,11 +115,6 @@ static inline bool SkImageInfoIsValidCommon(const SkImageInfo& info) {
         return false;
     }
 
-    if (kRGBA_F16_SkColorType == info.colorType() &&
-       (info.colorSpace() && (!info.colorSpace()->gammaIsLinear()))) {
-        return false;
-    }
-
     return true;
 }