Add implicit view ID constant

Author: loic-sharma

lib/ui/window/platform_configuration.cc

@@ -22,6 +22,8 @@
 namespace flutter {
 namespace {
 
+const int kImplicitViewId = 0;
+
 Dart_Handle ToByteData(const fml::Mapping& buffer) {
   return tonic::DartByteData::Create(buffer.GetMapping(), buffer.GetSize());
 }
@@ -67,8 +69,10 @@ void PlatformConfiguration::DidCreateIsolate() {
                   Dart_GetField(library, tonic::ToDart("_drawFrame")));
   report_timings_.Set(tonic::DartState::Current(),
                       Dart_GetField(library, tonic::ToDart("_reportTimings")));
-  windows_.insert(std::make_pair(
-      0, std::make_unique<Window>(0, ViewportMetrics{1.0, 0.0, 0.0, -1})));
+  windows_.insert(
+      std::make_pair(kImplicitViewId,
+                     std::make_unique<Window>(
+                         kImplicitViewId, ViewportMetrics{1.0, 0.0, 0.0, -1})));
 }
 
 void PlatformConfiguration::UpdateLocales(
@@ -430,9 +434,9 @@ Dart_Handle PlatformConfigurationNativeApi::ComputePlatformResolvedLocale(
 Dart_Handle PlatformConfigurationNativeApi::ImplicitViewEnabled() {
   UIDartState::ThrowIfUIOperationsProhibited();
   bool enabled = UIDartState::Current()
-      ->platform_configuration()
-      ->client()
-      ->ImplicitViewEnabled();
+                     ->platform_configuration()
+                     ->client()
+                     ->ImplicitViewEnabled();
 
   return Dart_NewBoolean(enabled);
 }