Make GrPipelineInput::setToSolidCoverage set the opaque bit.

Change-Id: I3580a9bf1b40c46ac642157f50e09b1fab40c3d3
Reviewed-on: https://skia-review.googlesource.com/8485
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/GrPipelineInput.h b/src/gpu/GrPipelineInput.h
index 17ec5f6..a0826ec 100644
--- a/src/gpu/GrPipelineInput.h
+++ b/src/gpu/GrPipelineInput.h
@@ -40,7 +40,7 @@
 
     void setToSolidCoverage() {
         fColor = GrColor_WHITE;
-        fFlags = kColorIsKnown_Flag | kColorIsKnown_Flag;
+        fFlags = kColorIsKnown_Flag | kIsOpaque_Flag;
     }
 
     void setToScalar(uint8_t alpha) {