Revert of Add isSingleComponent bool to getConstantColorComponent (patchset #6 id:100001 of https://codereview.chromium.org/608253002/)

Reason for revert:
Changing some GMs

Original issue's description:
> Add isSingleComponent bool to getConstantColorComponent
>
> Initial step to allowing effects to use/output 1 or 4 color/coverage components. This cl doesn't change any current logic and all effects still assume they are working with 4 components.
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/3b8af078281a5a20f951b9fd84f38d92b8f6217b

TBR=joshualitt@chromium.org,bsalomon@google.com,reed@google.com,egdaniel@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/617853003
diff --git a/src/gpu/effects/GrSimpleTextureEffect.cpp b/src/gpu/effects/GrSimpleTextureEffect.cpp
index a7707da..6743ddb 100644
--- a/src/gpu/effects/GrSimpleTextureEffect.cpp
+++ b/src/gpu/effects/GrSimpleTextureEffect.cpp
@@ -41,9 +41,8 @@
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void GrSimpleTextureEffect::onComputeInvariantOutput(InvariantOutput* inout) const {
-    this->updateInvariantOutputForModulation(inout);
-    inout->fIsSingleComponent = false;
+void GrSimpleTextureEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
+    this->updateConstantColorComponentsForModulation(color, validFlags);
 }
 
 const GrBackendFragmentProcessorFactory& GrSimpleTextureEffect::getFactory() const {