Bug 1612174 - [remote] Emit "init" lifecycleEvent when readyState is "loading" r=remote-protocol-reviewers,whimboo

Evaluating `document.open` + `write` + `close` triggers the `readyState`
to change to "loading". Puppeteer, for example, relies on a seeing an
"init" life cycle event in that case for their `Page.setContent` method.

Also move "Page.loadEventFired" to be triggered by an actual "load"
instead of "pagehide", which we don't see after a `document.write`.

Differential Revision: https://phabricator.services.mozilla.com/D67702

--HG--
extra : moz-landing-system : lando

remote/domains/content/Page.jsm

@@ -62,12 +62,24 @@ class Page extends ContentProcessDomain {
       this.enabled = true;
       this.contextObserver.on("frame-navigated", this._onFrameNavigated);
 
-      this.chromeEventHandler.addEventListener("DOMContentLoaded", this, {
+      this.chromeEventHandler.addEventListener("readystatechange", this, {
         mozSystemGroup: true,
+        capture: true,
       });
       this.chromeEventHandler.addEventListener("pagehide", this, {
         mozSystemGroup: true,
       });
+      this.chromeEventHandler.addEventListener("unload", this, {
+        mozSystemGroup: true,
+        capture: true,
+      });
+      this.chromeEventHandler.addEventListener("DOMContentLoaded", this, {
+        mozSystemGroup: true,
+      });
+      this.chromeEventHandler.addEventListener("load", this, {
+        mozSystemGroup: true,
+        capture: true,
+      });
       this.chromeEventHandler.addEventListener("pageshow", this, {
         mozSystemGroup: true,
       });
@@ -78,12 +90,24 @@ class Page extends ContentProcessDomain {
     if (this.enabled) {
       this.contextObserver.off("frame-navigated", this._onFrameNavigated);
 
-      this.chromeEventHandler.removeEventListener("DOMContentLoaded", this, {
+      this.chromeEventHandler.removeEventListener("readystatechange", this, {
         mozSystemGroup: true,
+        capture: true,
       });
       this.chromeEventHandler.removeEventListener("pagehide", this, {
         mozSystemGroup: true,
       });
+      this.chromeEventHandler.removeEventListener("unload", this, {
+        mozSystemGroup: true,
+        capture: true,
+      });
+      this.chromeEventHandler.removeEventListener("DOMContentLoaded", this, {
+        mozSystemGroup: true,
+      });
+      this.chromeEventHandler.removeEventListener("load", this, {
+        mozSystemGroup: true,
+        capture: true,
+      });
       this.chromeEventHandler.removeEventListener("pageshow", this, {
         mozSystemGroup: true,
       });
@@ -279,7 +303,7 @@ class Page extends ContentProcessDomain {
         }
         break;
 
-      case "pageshow":
+      case "load":
         this.emit("Page.loadEventFired", { timestamp });
         if (!isFrame) {
           this.emitLifecycleEvent(
@@ -293,8 +317,17 @@ class Page extends ContentProcessDomain {
         // XXX this should most likely be sent differently
         this.emit("Page.navigatedWithinDocument", { frameId, url });
         this.emit("Page.frameStoppedLoading", { frameId });
-
         break;
+
+      case "readystatechange":
+        if (this.content.document.readState === "loading") {
+          this.emitLifecycleEvent(
+            frameId,
+            /* loaderId */ null,
+            "init",
+            timestamp
+          );
+        }
     }
   }