Revert "Allow linear 8888 surface contexts in GPU backend."

This reverts commit 6a46fb210b810553b2a03a5f316109ccd9710ebc.

Reason for revert: breaks gms

Original change's description:
> Allow linear 8888 surface contexts in GPU backend.
> 
> Make SRGBReadWritePixels test test all combinations of sRGB, untagged, and linear.
> 
> Bug: skia:
> Change-Id: I0c75fa27b1bf60c6e7ce3b666ff79e1ad1c91b94
> Reviewed-on: https://skia-review.googlesource.com/106922
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: Brian Salomon <bsalomon@google.com>

TBR=bsalomon@google.com,brianosman@google.com

Change-Id: Ifb28fdde315ccc0b6fc1c9dd944ea319bafba754
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/107004
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/src/image/SkSurface_Gpu.cpp b/src/image/SkSurface_Gpu.cpp
index 03780c099e..04333ae508 100644
--- a/src/image/SkSurface_Gpu.cpp
+++ b/src/image/SkSurface_Gpu.cpp
@@ -261,11 +261,10 @@ bool SkSurface_Gpu::Valid(GrContext* context, GrPixelConfig config, SkColorSpace
             return context->caps()->srgbSupport() && colorSpace && colorSpace->gammaCloseToSRGB();
         case kRGBA_8888_GrPixelConfig:
         case kBGRA_8888_GrPixelConfig:
-            // We may get here with either a linear-gamma color space or with a sRGB-gamma color
-            // space when we lack GPU sRGB support.
+            // If we don't have sRGB support, we may get here with a color space. It still needs
+            // to be sRGB-like (so that the application will work correctly on sRGB devices.)
             return !colorSpace ||
-                   (colorSpace->gammaCloseToSRGB() && !context->caps()->srgbSupport()) ||
-                   colorSpace->gammaIsLinear();
+                (colorSpace->gammaCloseToSRGB() && !context->caps()->srgbSupport());
         default:
             return !colorSpace;
     }