Added SkSL workaround for devices which cannot safely access gl_FragCoord

This is the root cause of https://github.com/flutter/flutter/issues/13216
I've got a GM that demonstrates the bug, but only in Viewer.

Bug: skia:7410
Change-Id: Iaa1f27b10166aa09e4dc5949e5a6ca1bd14c99ac
Reviewed-on: https://skia-review.googlesource.com/93920
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/gpu/GrShaderCaps.cpp b/src/gpu/GrShaderCaps.cpp
index 2041ada635..2ab19478af 100644
--- a/src/gpu/GrShaderCaps.cpp
+++ b/src/gpu/GrShaderCaps.cpp
@@ -38,6 +38,7 @@ GrShaderCaps::GrShaderCaps(const GrContextOptions& options) {
     fRequiresLocalOutputColorForFBFetch = false;
     fMustObfuscateUniformColor = false;
     fMustGuardDivisionEvenAfterExplicitZeroCheck = false;
+    fCanUseFragCoord = true;
     fFlatInterpolationSupport = false;
     fPreferFlatInterpolation = false;
     fNoPerspectiveInterpolationSupport = false;
@@ -113,6 +114,7 @@ void GrShaderCaps::dumpJSON(SkJSONWriter* writer) const {
     writer->appendBool("Must obfuscate uniform color", fMustObfuscateUniformColor);
     writer->appendBool("Must guard division even after explicit zero check",
                        fMustGuardDivisionEvenAfterExplicitZeroCheck);
+    writer->appendBool("Can use gl_FragCoord", fCanUseFragCoord);
     writer->appendBool("Flat interpolation support", fFlatInterpolationSupport);
     writer->appendBool("Prefer flat interpolation", fPreferFlatInterpolation);
     writer->appendBool("No perspective interpolation support", fNoPerspectiveInterpolationSupport);