Revert "Fix precision caps and rrect/ellipse effect precisions"

This reverts commit e42180022720f2fcfd3c634cad855506a7940591.

Reason for revert: Also may be responsible for layout test failures? Playing it safe.

Original change's description:
> Fix precision caps and rrect/ellipse effect precisions
> 
> Replaces all the complex precision caps with a single flag that says
> whether "float" == fp32. Updates the ellipse and rrect effects to
> use float coords, and use the scale workaround when float != fp32.
> 
> Bug: skia:7190
> Change-Id: Ieccff9f38acd05e5cec78fe90d01a5da901a9307
> Reviewed-on: https://skia-review.googlesource.com/70961
> Commit-Queue: Chris Dalton <csmartdalton@google.com>
> Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>

TBR=egdaniel@google.com,bsalomon@google.com,csmartdalton@google.com,ethannicholas@google.com

Change-Id: Idca2f0390e7a0eb85010255183f2f27332b8d26d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:7190
Reviewed-on: https://skia-review.googlesource.com/72540
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/tests/SRGBReadWritePixelsTest.cpp b/tests/SRGBReadWritePixelsTest.cpp
index b5d61c1..6ebdcf7 100644
--- a/tests/SRGBReadWritePixelsTest.cpp
+++ b/tests/SRGBReadWritePixelsTest.cpp
@@ -184,14 +184,14 @@
             return;
         }
 
-        float error = context->caps()->shaderCaps()->halfIs32Bits() ? 0.5f : 1.2f;
+        float error = context->caps()->shaderCaps()->floatPrecisionVaries() ? 1.2f  : 0.5f;
 
         // Write srgba data and read as srgba and then as rgba
         if (sContext->writePixels(iiSRGBA, origData, 0, 0, 0)) {
             // For the all-srgba case, we allow a small error only for devices that have
             // precision variation because the srgba data gets converted to linear and back in
             // the shader.
-            float smallError = context->caps()->shaderCaps()->halfIs32Bits() ? 0.0f : 1.f;
+            float smallError = context->caps()->shaderCaps()->floatPrecisionVaries() ? 1.f : 0.0f;
             read_and_check_pixels(reporter, sContext.get(), origData, iiSRGBA,
                                   check_srgb_to_linear_to_srgb_conversion, smallError,
                                   "write/read srgba to srgba texture");