Resubmit issue 2221103002 to fix the iOS build by declaring the flag in

samplecode/SampleApp.cpp

Index: samplecode/SampleApp.cpp
diff --git a/samplecode/SampleApp.cpp b/samplecode/SampleApp.cpp
index 233306c767815a0585e064818061a5352d1c5af9..385268ef021eb75da9284bebbab036908ad08ac7 100644
--- a/samplecode/SampleApp.cpp
+++ b/samplecode/SampleApp.cpp
@@ -33,6 +33,7 @@
 #include "SkTypeface.h"
 #include "SkWindow.h"
 #include "sk_tool_utils.h"
+#include "SkScan.h"
 
 #include "SkReadBuffer.h"
 #include "SkStream.h"
@@ -1800,6 +1801,11 @@ bool SampleWindow::onHandleChar(SkUnichar uni) {
                 this->inval(nullptr);
             }
             break;
+        case 'A':
+            GlobalAAConfig::getInstance().fUseAnalyticAA =
+                    !GlobalAAConfig::getInstance().fUseAnalyticAA;
+            this->inval(nullptr);
+            break;
         case 'B':
             post_event_to_sink(new SkEvent("PictFileView::toggleBBox"), curr_view(this));
             // Cannot call updateTitle() synchronously, because the toggleBBox event is still in