Replace targetHasUnifiedMultisampling in GrPB constructor

Replaces targetHasUnifiedMultisampling with a simpler "useHWAA". Now
the code that creates a pipeline builder needs to decide on its own
whether it should enable multisampling, rather than relying on the
builder to try and guess.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2041283002

Review-Url: https://codereview.chromium.org/2041283002
diff --git a/src/gpu/GrPipelineBuilder.cpp b/src/gpu/GrPipelineBuilder.cpp
index 04967a7..f7848ba 100644
--- a/src/gpu/GrPipelineBuilder.cpp
+++ b/src/gpu/GrPipelineBuilder.cpp
@@ -22,7 +22,7 @@
     SkDEBUGCODE(fBlockEffectRemovalCnt = 0;)
 }
 
-GrPipelineBuilder::GrPipelineBuilder(const GrPaint& paint, bool targetHasUnifiedMultisampling)
+GrPipelineBuilder::GrPipelineBuilder(const GrPaint& paint, bool useHWAA)
     : GrPipelineBuilder() {
     SkDEBUGCODE(fBlockEffectRemovalCnt = 0;)
 
@@ -36,8 +36,7 @@
 
     fXPFactory.reset(SkSafeRef(paint.getXPFactory()));
 
-    this->setState(GrPipelineBuilder::kHWAntialias_Flag,
-                   targetHasUnifiedMultisampling && paint.isAntiAlias());
+    this->setState(GrPipelineBuilder::kHWAntialias_Flag, useHWAA);
     this->setState(GrPipelineBuilder::kDisableOutputConversionToSRGB_Flag,
                    paint.getDisableOutputConversionToSRGB());
     this->setState(GrPipelineBuilder::kAllowSRGBInputs_Flag,