Revert "Allow FPs to elevate default precision for the entire fragment program"

This reverts commit 92d7ccafdf896cf19764e025873d13315a76842d.

Reason for revert: Vulkan errors.

Original change's description:
> Allow FPs to elevate default precision for the entire fragment program
> 
> Currently, GrConfigConversionEffect is able to round-trip on many mobile
> GPUs because it uses highp for all intermediate variables (including the
> texture fetch result). Separating the texture sample into a different
> processor breaks that.
> 
> This is a blunt instrument, not to be used lightly.
> 
> Bug: skia:
> Change-Id: I2ab365e3da79628069e2eb727c43c2bf45bfd789
> Reviewed-on: https://skia-review.googlesource.com/10162
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>
> 

TBR=bsalomon@google.com,robertphillips@google.com,brianosman@google.com,ethannicholas@google.com,reviews@skia.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: Iee5bb409f86a9cabecc76bd1273a5b3cef6af179
Reviewed-on: https://skia-review.googlesource.com/10967
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/bench/GLVec4ScalarBench.cpp b/bench/GLVec4ScalarBench.cpp
index b5c7e22a49..26f9220750 100644
--- a/bench/GLVec4ScalarBench.cpp
+++ b/bench/GLVec4ScalarBench.cpp
@@ -131,7 +131,7 @@ GrGLuint GLVec4ScalarBench::setupShader(const GrGLContext* ctx) {
     // next stage.
     GrShaderVar oFragColor("o_FragColor", kVec4f_GrSLType, GrShaderVar::kOut_TypeModifier);
     SkString fshaderTxt(version);
-    GrGLSLAppendDefaultFloatPrecisionDeclaration(kMedium_GrSLPrecision, *shaderCaps, &fshaderTxt);
+    GrGLSLAppendDefaultFloatPrecisionDeclaration(kDefault_GrSLPrecision, *shaderCaps, &fshaderTxt);
     oPosition.setTypeModifier(GrShaderVar::kIn_TypeModifier);
     oPosition.appendDecl(shaderCaps, &fshaderTxt);
     fshaderTxt.append(";\n");