Fix dashing bug where hwaa was unintentionally disabled

src/gpu/batches/GrDashLinePathRenderer.cpp

Index: src/gpu/batches/GrDashLinePathRenderer.cpp
diff --git a/src/gpu/batches/GrDashLinePathRenderer.cpp b/src/gpu/batches/GrDashLinePathRenderer.cpp
index 51ef0528aa1634cf72e9820da25bf0a9e7b65904..d75ca38b7d02562ca40860b19697e753e35d45fd 100644
--- a/src/gpu/batches/GrDashLinePathRenderer.cpp
+++ b/src/gpu/batches/GrDashLinePathRenderer.cpp
@@ -22,11 +22,15 @@ bool GrDashLinePathRenderer::onCanDrawPath(const CanDrawPathArgs& args) const {
 bool GrDashLinePathRenderer::onDrawPath(const DrawPathArgs& args) {
     GR_AUDIT_TRAIL_AUTO_FRAME(args.fDrawContext->auditTrail(),
                               "GrDashLinePathRenderer::onDrawPath");
-    bool msaaIsEnabled = args.fDrawContext->isUnifiedMultisampled();
+    // We always take the msaa codepath, regardless of paint aa, if the platform won't be able to
+    // disable multisampling. Dashes use a mix of msaa and coverage aa, so if we took the bw path in
+    // this case we would wind up with external edges antialiased and internal edges unantialiased.
+    bool useHWAA = args.fDrawContext->isUnifiedMultisampled() &&
+                   (!args.fDrawContext->caps()->multisampleDisableSupport() ||
+                    args.fPaint->isAntiAlias());
+
     GrDashingEffect::AAMode aaMode;
-    if (msaaIsEnabled) {
-        // We ignore args.fAntiAlias here and force anti aliasing when using MSAA. Otherwise,
-        // we can wind up with external edges antialiased and internal edges unantialiased.
+    if (useHWAA) {
         aaMode = GrDashingEffect::AAMode::kCoverageWithMSAA;
     } else if (args.fAntiAlias) {
         aaMode = GrDashingEffect::AAMode::kCoverage;
@@ -44,7 +48,8 @@ bool GrDashLinePathRenderer::onDrawPath(const DrawPathArgs& args) {
         return false;
     }
 
-    GrPipelineBuilder pipelineBuilder(*args.fPaint, msaaIsEnabled);
+    GrPipelineBuilder pipelineBuilder(*args.fPaint, args.fDrawContext->isUnifiedMultisampled());
+    pipelineBuilder.setState(GrPipelineBuilder::kHWAntialias_Flag, useHWAA);
     pipelineBuilder.setUserStencil(args.fUserStencilSettings);
 
     args.fDrawContext->drawBatch(pipelineBuilder, *args.fClip, batch);