Replace Snowpack and Parcel with esbuild.

Change-Id: I4fac1339a798fe05e4a4e7bc547561a09a756de0
diff --git a/build.xml b/build.xml
index d80c6b2..14d1948 100644
--- a/build.xml
+++ b/build.xml
@@ -23,57 +23,25 @@
     </condition>
   </target>
 
-  <target name="snowpack" depends="snowpack.check,yarn" if="snowpack.run">
-    <!-- Build for development -->
+  <target name="esbuild" depends="esbuild.check,yarn" if="esbuild.run">
     <exec executable="yarn" dir="${web-dir}">
       <arg value="run"/>
-      <arg value="snowpack"/>
-    </exec>
-  </target>
-
-  <target name="snowpack.check">
-    <condition property="snowpack.run">
-      <not>
-        <available file="${web-dir}/web_modules"/>
-      </not>
-    </condition>
-  </target>
-
-  <target name="snowpack-build" depends="snowpack-build.check,yarn" if="snowpack-build.run">
-    <!-- Build for distribution -->
-    <exec executable="yarn" dir="${web-dir}">
-      <arg value="run"/>
-      <arg value="snowpack"/>
       <arg value="build"/>
     </exec>
   </target>
 
-  <target name="snowpack-build.check">
-    <condition property="snowpack-build.run">
+  <target name="esbuild.check">
+    <condition property="esbuild.run">
       <not>
-        <available file="${web-dir}/build/web_modules"/>
+        <and>
+          <available file="${web-dir}/web_modules"/>
+          <available file="${web-dir}/dist"/>
+        </and>
       </not>
     </condition>
   </target>
 
-  <target name="parcel" depends="parcel.check,yarn" if="parcel.run">
-    <exec executable="yarn" dir="${web-dir}">
-      <arg value="parcel"/>
-      <arg value="build"/>
-      <arg value="lib.css"/>
-      <arg value="lib.js"/>
-    </exec>
-  </target>
-
-  <target name="parcel.check">
-    <condition property="parcel.run">
-      <not>
-        <available file="${web-dir}/dist"/>
-      </not>
-    </condition>
-  </target>
-
-  <target name="flow" depends="snowpack">
+  <target name="flow" depends="esbuild">
     <exec executable="yarn" dir="${web-dir}">
       <arg value="run"/>
       <arg value="flow"/>
@@ -81,7 +49,7 @@
     </exec>
   </target>
 
-  <target name="eslint" depends="snowpack">
+  <target name="eslint" depends="esbuild">
     <exec executable="yarn" dir="${web-dir}">
       <arg value="run"/>
       <arg value="eslint"/>
@@ -94,9 +62,9 @@
     </exec>
   </target>
 
-  <target name="web.resources" depends="snowpack,snowpack-build" unless="skip-web"/>
+  <target name="web.resources" depends="esbuild" unless="skip-web"/>
   <target name="web.check" unless="skip-web" depends="web.resources,flow,eslint"/>
-  <target name="web.bundle" unless="skip-web" depends="web.resources,parcel"/>
+  <target name="web.bundle" unless="skip-web" depends="web.resources"/>
   <target name="web" unless="skip-web" depends="web.resources,web.check,web.bundle" description="Generate web resources"/>
 
   <target name="package" description="Create executable JAR">