Skip the sRGB mip-map testing on command buffer

Chromium command buffer now has the sRGB decode extension, but it doesn't
make any guarantees about the interaction with glGenerateMipmap.

BUG=skia:

Review-Url: https://codereview.chromium.org/2557603006

src/gpu/gl/GrGLCaps.cpp

@@ -52,6 +52,7 @@ GrGLCaps::GrGLCaps(const GrContextOptions& contextOptions,
     fRGBAToBGRAReadbackConversionsAreSlow = false;
     fDoManualMipmapping = false;
     fSRGBDecodeDisableSupport = false;
+    fSRGBDecodeDisableAffectsMipmaps = false;
 
     fBlitFramebufferFlags = kNoSupport_BlitFramebufferFlag;
 
@@ -609,6 +610,8 @@ void GrGLCaps::init(const GrContextOptions& contextOptions,
     }
 
     fSRGBDecodeDisableSupport = ctxInfo.hasExtension("GL_EXT_texture_sRGB_decode");
+    fSRGBDecodeDisableAffectsMipmaps = fSRGBDecodeDisableSupport &&
+        kChromium_GrGLDriver != ctxInfo.driver();
 
     // Requires fTextureRedSupport, fTextureSwizzleSupport, msaa support, ES compatibility have
     // already been detected.

src/gpu/gl/GrGLCaps.h

@@ -346,6 +346,7 @@ public:
     bool doManualMipmapping() const { return fDoManualMipmapping; }
 
     bool srgbDecodeDisableSupport() const { return fSRGBDecodeDisableSupport; }
+    bool srgbDecodeDisableAffectsMipmaps() const { return fSRGBDecodeDisableAffectsMipmaps; }
 
     /**
      * Returns a string containing the caps info.
@@ -424,6 +425,7 @@ private:
     bool fRGBAToBGRAReadbackConversionsAreSlow : 1;
     bool fDoManualMipmapping : 1;
     bool fSRGBDecodeDisableSupport : 1;
+    bool fSRGBDecodeDisableAffectsMipmaps : 1;
 
     uint32_t fBlitFramebufferFlags;
 

tests/SRGBMipMapTest.cpp

@@ -148,10 +148,14 @@ DEF_GPUTEST_FOR_GL_RENDERING_CONTEXTS(SRGBMipMaps, reporter, ctxInfo) {
     // skbug.com/5048). On GL, we may not have sRGB decode support. In that case, rendering sRGB
     // textures to a legacy surface produces nonsense, so this part of the test is meaningless.
     //
+    // We also skip this part of the test on command buffer (via srgbDecodeDisableAffectsMipmaps),
+    // because that implementation of the extension doesn't ensure that mips respect the setting.
+    //
     // TODO: Once Vulkan supports legacy mip-mapping, we can promote this to GrCaps. Right now,
     // Vulkan has most of the functionality, but not the mip-mapping part that's being tested here.
     GrGLGpu* glGpu = static_cast<GrGLGpu*>(context->getGpu());
-    if (glGpu->glCaps().srgbDecodeDisableSupport()) {
+    if (glGpu->glCaps().srgbDecodeDisableSupport() &&
+        glGpu->glCaps().srgbDecodeDisableAffectsMipmaps()) {
         read_and_check_pixels(reporter, l32RenderTargetContext->asTexture().get(), expectedLinear,
                               error, "re-render as linear");
     }