Android: Add failOnWarnings check to android build.gradle and configure lint as warnings as error

Author: Sangamesh1997

android/build.gradle

@@ -20,7 +20,15 @@ android {
         versionName "1.0"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
-    lintOptions { abortOnError true }
+
+    //fail on android lint warnings if failOnWarning is set true
+    lintOptions {
+        abortOnError true
+        if (rootProject.hasProperty("failOnWarnings") && rootProject.failOnWarnings.toBoolean()) {
+            warningsAsErrors true
+        }
+    }
+
     publishing {
         singleVariant('release') {
             withSourcesJar()
@@ -44,6 +52,14 @@ dependencies {
     testImplementation libraries.truth
 }
 
+//Enforce -Werror on java compiler if failOnWarning is set
+tasks.withType(JavaCompile).configureEach {
+    it.options.compilerArgs += ["-Xlint:all"]
+    if (rootProject.hasProperty("failOnWarnings") && rootProject.failOnWarnings.toBoolean()) {
+        it.options.compilerArgs += ["-Werror"]
+    }
+}
+
 tasks.register("javadocs", Javadoc) {
     source = android.sourceSets.main.java.srcDirs
     classpath += files(android.getBootClasspath())