Make BeforeInstallPromptEvent cancelable

third_party/WebKit/Source/modules/app_banner/BeforeInstallPromptEvent.cpp

Index: third_party/WebKit/Source/modules/app_banner/BeforeInstallPromptEvent.cpp
diff --git a/third_party/WebKit/Source/modules/app_banner/BeforeInstallPromptEvent.cpp b/third_party/WebKit/Source/modules/app_banner/BeforeInstallPromptEvent.cpp
index 1d78fb2383aaa40a9aa9c30acaecacf0d0cdabed..405e3ef3cf1f563f5f95eb15ccde5e65370d984e 100644
--- a/third_party/WebKit/Source/modules/app_banner/BeforeInstallPromptEvent.cpp
+++ b/third_party/WebKit/Source/modules/app_banner/BeforeInstallPromptEvent.cpp
@@ -34,7 +34,7 @@ BeforeInstallPromptEvent::BeforeInstallPromptEvent(
 BeforeInstallPromptEvent::BeforeInstallPromptEvent(
     const AtomicString& name,
     const BeforeInstallPromptEventInit& init)
-    : Event(name, false, true), m_binding(this), m_promptCalled(false) {
+    : Event(name, init), m_binding(this), m_promptCalled(false) {
   if (init.hasPlatforms())
     m_platforms = init.platforms();
 }
@@ -59,7 +59,7 @@ ScriptPromise BeforeInstallPromptEvent::userChoice(ScriptState* scriptState) {
     return m_userChoice->promise(scriptState->world());
   return ScriptPromise::rejectWithDOMException(
       scriptState,
-      DOMException::create(InvalidStateError,
+      DOMException::create(NotAllowedError,

[Matt Giuca, 2017/04/26 05:28:50]

This is technically a breaking change (though NOBODY should be relying on it).

I've sent an email to the team asking whether we can make such a change without
an Intent email.

[Matt Giuca, 2017/05/11 01:42:05]

Per https://crbug.com/658639, this bug was a mistake (it was originally speced
as InvalidStateError) so you can remove this change.

Actually the spec no longer calls for ANY exception here. I've asked if it's a
mistake on https://github.com/w3c/manifest/issues/577, but in the mean time,
let's just keep the Chrome behaviour as-is.

This means you should update the CL description to not mention changing the
exception type, and remove the reference to bug 658639.

[dominickn, 2017/05/11 01:51:57]

Done.

                            "userChoice cannot be accessed on this event."));
 }
 
@@ -69,7 +69,7 @@ ScriptPromise BeforeInstallPromptEvent::prompt(ScriptState* scriptState) {
   if (!defaultPrevented() || m_promptCalled || !m_bannerService.is_bound()) {
     return ScriptPromise::rejectWithDOMException(
         scriptState,
-        DOMException::create(InvalidStateError,
+        DOMException::create(NotAllowedError,
                              "The prompt() method may only be called once, "
                              "following preventDefault()."));
   }