Implement "appinstalled" event on Android.

third_party/WebKit/Source/core/events/EventTarget.cpp

Index: third_party/WebKit/Source/core/events/EventTarget.cpp
diff --git a/third_party/WebKit/Source/core/events/EventTarget.cpp b/third_party/WebKit/Source/core/events/EventTarget.cpp
index 0814cb3a6188a26a4510f353648aa3c1e4537e48..fc5d07dd42c589d9b08403fa5004666aeb85fddd 100644
--- a/third_party/WebKit/Source/core/events/EventTarget.cpp
+++ b/third_party/WebKit/Source/core/events/EventTarget.cpp
@@ -309,6 +309,11 @@ void EventTarget::addedEventListener(
       UseCounter::count(executingWindow->document(),
                         UseCounter::AuxclickAddListenerCount);
     }
+  } else if (eventType == EventTypeNames::appinstalled) {
+    if (LocalDOMWindow* executingWindow = this->executingWindow()) {
+      UseCounter::count(executingWindow->document(),
+                        UseCounter::AppInstalledEventAddListener);
+    }
   } else if (EventUtil::isPointerEventType(eventType)) {
     if (LocalDOMWindow* executingWindow = this->executingWindow()) {
       UseCounter::count(executingWindow->document(),