Implement a Mojo service for Background Fetch

third_party/WebKit/Source/modules/background_fetch/BackgroundFetchedEvent.cpp

Index: third_party/WebKit/Source/modules/background_fetch/BackgroundFetchedEvent.cpp
diff --git a/third_party/WebKit/Source/modules/background_fetch/BackgroundFetchedEvent.cpp b/third_party/WebKit/Source/modules/background_fetch/BackgroundFetchedEvent.cpp
index d5cc50da50f26fc97d8016b63f06b37a45a91a44..3551dbe69457edbdc4634f9f4b4e486765e4fc68 100644
--- a/third_party/WebKit/Source/modules/background_fetch/BackgroundFetchedEvent.cpp
+++ b/third_party/WebKit/Source/modules/background_fetch/BackgroundFetchedEvent.cpp
@@ -4,9 +4,11 @@
 
 #include "modules/background_fetch/BackgroundFetchedEvent.h"
 
+#include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "core/dom/DOMException.h"
 #include "modules/EventModulesNames.h"
+#include "modules/background_fetch/BackgroundFetchBridge.h"
 #include "modules/background_fetch/BackgroundFetchSettledRequest.h"
 #include "modules/background_fetch/BackgroundFetchedEventInit.h"
 
@@ -14,9 +16,11 @@ namespace blink {
 
 BackgroundFetchedEvent::BackgroundFetchedEvent(
     const AtomicString& type,
-    const BackgroundFetchedEventInit& init)
+    const BackgroundFetchedEventInit& init,
+    ServiceWorkerRegistration* registration)
     : BackgroundFetchEvent(type, init),
-      m_completedFetches(init.completedFetches()) {}
+      m_completedFetches(init.completedFetches()),
+      m_registration(registration) {}
 
 BackgroundFetchedEvent::~BackgroundFetchedEvent() = default;
 
@@ -26,10 +30,37 @@ BackgroundFetchedEvent::completedFetches() const {
 }
 
 ScriptPromise BackgroundFetchedEvent::updateUI(ScriptState* scriptState,
-                                               String title) {
-  return ScriptPromise::rejectWithDOMException(
-      scriptState,
-      DOMException::create(NotSupportedError, "Not implemented yet."));
+                                               const String& title) {
+  if (!m_registration) {
+    // Return a Promise that will never settle when a developer calls this
+    // method on a BackgroundFetchedEvent instance they created themselves.
+    return ScriptPromise();
+  }
+
+  ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
+  ScriptPromise promise = resolver->promise();
+
+  BackgroundFetchBridge::from(m_registration)
+      ->updateUI(tag(), title,
+                 WTF::bind(&BackgroundFetchedEvent::didUpdateUI,
+                           wrapPersistent(this), wrapPersistent(resolver)));
+
+  return promise;
+}
+
+void BackgroundFetchedEvent::didUpdateUI(
+    ScriptPromiseResolver* resolver,
+    mojom::blink::BackgroundFetchError error) {
+  switch (error) {
+    case mojom::blink::BackgroundFetchError::NONE:
+      resolver->resolve();
+      return;
+    case mojom::blink::BackgroundFetchError::DUPLICATED_TAG:
+      // Not applicable for this callback.
+      break;
+  }
+
+  NOTREACHED();
 }
 
 const AtomicString& BackgroundFetchedEvent::interfaceName() const {
@@ -38,6 +69,7 @@ const AtomicString& BackgroundFetchedEvent::interfaceName() const {
 
 DEFINE_TRACE(BackgroundFetchedEvent) {
   visitor->trace(m_completedFetches);
+  visitor->trace(m_registration);
   BackgroundFetchEvent::trace(visitor);
 }