Update XPF invariant info to not account for conflation

src/gpu/GrDrawContext.cpp

Index: src/gpu/GrDrawContext.cpp
diff --git a/src/gpu/GrDrawContext.cpp b/src/gpu/GrDrawContext.cpp
index 29318862cd0cb63bcd345b741d0a87a16c49913b..92a1e36f1881b1015e732b9c2dbda7642253615c 100644
--- a/src/gpu/GrDrawContext.cpp
+++ b/src/gpu/GrDrawContext.cpp
@@ -412,7 +412,7 @@ void GrDrawContext::drawRect(GrRenderTarget* rt,
                 rect_contains_inclusive(rect, srcSpaceRTQuad[3])) {
                 // Will it blend?
                 GrColor clearColor;
-                if (paint.isOpaqueAndConstantColor(&clearColor)) {
+                if (paint.isConstantBlendedColor(&clearColor)) {
                     fDrawTarget->clear(NULL, clearColor, true, rt);
                     return;
                 }