Migrate DefaultHttpDataSourceTest from Mockito to MockWebServer

PiperOrigin-RevId: 317636681

constants.gradle

@@ -23,6 +23,7 @@ project.ext {
     junitVersion = '4.13-rc-2'
     guavaVersion = '27.1-android'
     mockitoVersion = '2.25.0'
+    mockWebServerVersion = '3.12.0'
     robolectricVersion = '4.4-SNAPSHOT'
     checkerframeworkVersion = '2.5.0'
     jsr305Version = '3.0.2'

library/core/build.gradle

@@ -66,6 +66,7 @@ dependencies {
         exclude module: modulePrefix.substring(1) + 'library-core'
     }
     testImplementation 'com.google.guava:guava:' + guavaVersion
+    testImplementation 'com.squareup.okhttp3:mockwebserver:' + mockWebServerVersion
     testImplementation 'org.robolectric:robolectric:' + robolectricVersion
     testImplementation project(modulePrefix + 'testutils')
 }