Enable blend optimizations with instanced draws

src/gpu/instanced/InstancedRendering.cpp

Index: src/gpu/instanced/InstancedRendering.cpp
diff --git a/src/gpu/instanced/InstancedRendering.cpp b/src/gpu/instanced/InstancedRendering.cpp
index 165bff494b3fa0ab1f241c844ec59afb8b582da9..adb0738967cff82c429c54453b30c0946e8b70af 100644
--- a/src/gpu/instanced/InstancedRendering.cpp
+++ b/src/gpu/instanced/InstancedRendering.cpp
@@ -328,6 +328,20 @@ void InstancedRendering::Batch::appendParamsTexel(SkScalar x, SkScalar y, SkScal
     fInfo.fHasParams = true;
 }
 
+void InstancedRendering::Batch::computePipelineOptimizations(GrInitInvariantOutput* color,
+                                                            GrInitInvariantOutput* coverage,
+                                                            GrBatchToXPOverrides* overrides) const {
+    color->setKnownFourComponents(this->getSingleInstance().fColor);
+
+    if (AntialiasMode::kCoverage == fInfo.fAntialiasMode ||
+        (AntialiasMode::kNone == fInfo.fAntialiasMode &&
+         !fInfo.isSimpleRects() && fInfo.fCannotDiscard)) {
+        coverage->setUnknownSingleComponent();
+    } else {
+        coverage->setKnownSingleComponent(255);
+    }
+}
+
 void InstancedRendering::Batch::initBatchTracker(const GrXPOverridesForBatch& overrides) {
     Draw& draw = this->getSingleDraw(); // This will assert if we have > 1 command.
     SkASSERT(draw.fGeometry.isEmpty());
@@ -389,22 +403,6 @@ bool InstancedRendering::Batch::onCombineIfPossible(GrBatch* other, const GrCaps
     return true;
 }
 
-void InstancedRendering::Batch::computePipelineOptimizations(GrInitInvariantOutput* color,
-                                                            GrInitInvariantOutput* coverage,
-                                                            GrBatchToXPOverrides* overrides) const {
-    // We need to be careful about fInfo here and consider how it might change as batches combine.
-    // e.g. We can't make an assumption based on fInfo.isSimpleRects() because the batch might
-    // later combine with a non-rect.

[csmartdalton, 2016/07/03 17:36:43]

This comment was actually just about a bug, fixed here:
https://codereview.chromium.org/2120153002/

-    color->setUnknownFourComponents();
-    if (fInfo.fAntialiasMode >= AntialiasMode::kMSAA) {
-        coverage->setKnownSingleComponent(255);
-    } else if (AntialiasMode::kNone == fInfo.fAntialiasMode && !fInfo.fCannotDiscard) {
-        coverage->setKnownSingleComponent(255);
-    } else {
-        coverage->setUnknownSingleComponent();
-    }
-}
-
 void InstancedRendering::beginFlush(GrResourceProvider* rp) {
     SkASSERT(State::kRecordingDraws == fState);
     fState = State::kFlushing;