Bug 1731613 - Move GetProcessSwitchBehavior method to C++, r=nika

Differential Revision: https://phabricator.services.mozilla.com/D128898

dom/interfaces/base/nsIBrowser.idl

@@ -129,28 +129,6 @@ interface nsIBrowser : nsISupports
                                in uint64_t aRequestContextID,
                                in AString aContentType);
 
-  /**
-   * Determine what process switching behavior this browser element should have.
-   */
-  cenum ProcessBehavior : 8 {
-    // Gecko won't automatically change which process this frame, or it's
-    // subframes, are loaded in.
-    PROCESS_BEHAVIOR_DISABLED,
-
-    // If `useRemoteTabs` is enabled, Gecko will change which process this frame
-    // is loaded in automatically, without calling `performProcessSwitch`.
-    // When `useRemoteSubframes` is enabled, subframes will change processes.
-    PROCESS_BEHAVIOR_STANDARD,
-
-    // Gecko won't automatically change which process this frame is loaded, but
-    // when `useRemoteSubframes` is enabled, subframes will change processes.
-    //
-    // NOTE: This configuration is included only for backwards compatibility,
-    // and will be removed, as it can easily lead to invalid behavior.
-    PROCESS_BEHAVIOR_SUBFRAME_ONLY,
-  };
-  readonly attribute nsIBrowser_ProcessBehavior processSwitchBehavior;
-
   /**
    * Called to perform any async tasks which must be completed before changing
    * remoteness. Gecko will wait for the returned promise to resolve before

netwerk/ipc/DocumentLoadListener.cpp

@@ -1467,6 +1467,21 @@ void DocumentLoadListener::SerializeRedirectData(
   }
 }
 
+DocumentLoadListener::ProcessBehavior GetProcessSwitchBehavior(
+    Element* aBrowserElement) {
+  if (aBrowserElement->HasAttribute(u"maychangeremoteness"_ns)) {
+    return DocumentLoadListener::ProcessBehavior::PROCESS_BEHAVIOR_STANDARD;
+  }
+  nsCOMPtr<nsIBrowser> browser = aBrowserElement->AsBrowser();
+  bool isRemoteBrowser = false;
+  browser->GetIsRemoteBrowser(&isRemoteBrowser);
+  if (isRemoteBrowser) {
+    return DocumentLoadListener::ProcessBehavior::
+        PROCESS_BEHAVIOR_SUBFRAME_ONLY;
+  }
+  return DocumentLoadListener::ProcessBehavior::PROCESS_BEHAVIOR_DISABLED;
+}
+
 static bool ContextCanProcessSwitch(CanonicalBrowsingContext* aBrowsingContext,
                                     WindowGlobalParent* aParentWindow) {
   if (NS_WARN_IF(!aBrowsingContext)) {
@@ -1507,26 +1522,20 @@ static bool ContextCanProcessSwitch(CanonicalBrowsingContext* aBrowsingContext,
     return false;
   }
 
-  nsIBrowser::ProcessBehavior processBehavior =
-      nsIBrowser::PROCESS_BEHAVIOR_DISABLED;
-  nsresult rv = browser->GetProcessSwitchBehavior(&processBehavior);
-  if (NS_FAILED(rv)) {
-    MOZ_ASSERT_UNREACHABLE(
-        "nsIBrowser::GetProcessSwitchBehavior shouldn't fail");
-    MOZ_LOG(gProcessIsolationLog, LogLevel::Warning,
-            ("Process Switch Abort: failed to get process switch behavior"));
-    return false;
-  }
+  DocumentLoadListener::ProcessBehavior processBehavior =
+      GetProcessSwitchBehavior(browserElement);
 
   // Check if the process switch we're considering is disabled by the
   // <browser>'s process behavior.
-  if (processBehavior == nsIBrowser::PROCESS_BEHAVIOR_DISABLED) {
+  if (processBehavior ==
+      DocumentLoadListener::ProcessBehavior::PROCESS_BEHAVIOR_DISABLED) {
     MOZ_LOG(gProcessIsolationLog, LogLevel::Warning,
             ("Process Switch Abort: switch disabled by <browser>"));
     return false;
   }
-  if (!aParentWindow &&
-      processBehavior == nsIBrowser::PROCESS_BEHAVIOR_SUBFRAME_ONLY) {
+  if (!aParentWindow && processBehavior ==
+                            DocumentLoadListener::ProcessBehavior::
+                                PROCESS_BEHAVIOR_SUBFRAME_ONLY) {
     MOZ_LOG(gProcessIsolationLog, LogLevel::Warning,
             ("Process Switch Abort: toplevel switch disabled by <browser>"));
     return false;

netwerk/ipc/DocumentLoadListener.h

@@ -289,6 +289,25 @@ class DocumentLoadListener : public nsIInterfaceRequestor,
 
   bool IsDocumentLoad() const { return mIsDocumentLoad; }
 
+  // Determine what process switching behavior a browser element should have.
+  enum ProcessBehavior : uint8_t {
+    // Gecko won't automatically change which process this frame, or it's
+    // subframes, are loaded in.
+    PROCESS_BEHAVIOR_DISABLED,
+
+    // If `useRemoteTabs` is enabled, Gecko will change which process this frame
+    // is loaded in automatically, without calling `performProcessSwitch`.
+    // When `useRemoteSubframes` is enabled, subframes will change processes.
+    PROCESS_BEHAVIOR_STANDARD,
+
+    // Gecko won't automatically change which process this frame is loaded, but
+    // when `useRemoteSubframes` is enabled, subframes will change processes.
+    //
+    // NOTE: This configuration is included only for backwards compatibility,
+    // and will be removed, as it can easily lead to invalid behavior.
+    PROCESS_BEHAVIOR_SUBFRAME_ONLY,
+  };
+
  protected:
   virtual ~DocumentLoadListener();
 

toolkit/content/widgets/browser-custom-element.js

@@ -1803,25 +1803,6 @@
       return origins;
     }
 
-    get processSwitchBehavior() {
-      // If a `remotenessChangeHandler` is attached to this browser, it supports
-      // having its toplevel process switched dynamically in response to
-      // navigations.
-      if (this.hasAttribute("maychangeremoteness")) {
-        return Ci.nsIBrowser.PROCESS_BEHAVIOR_STANDARD;
-      }
-
-      // For backwards compatibility, we need to mark remote, but
-      // non-`allowremote`, frames as `PROCESS_BEHAVIOR_SUBFRAME_ONLY`, as some
-      // tests rely on it.
-      // FIXME: Remove this?
-      if (this.isRemoteBrowser) {
-        return Ci.nsIBrowser.PROCESS_BEHAVIOR_SUBFRAME_ONLY;
-      }
-      // Otherwise, don't allow gecko-initiated toplevel process switches.
-      return Ci.nsIBrowser.PROCESS_BEHAVIOR_DISABLED;
-    }
-
     // This method is replaced by frontend code in order to delay performing the
     // process switch until some async operatin is completed.
     //