Bug 1626573 - P1 - BrowsingContext transmits BlobURL before loading an URI if URI is a BlobURL r=baku

Differential Revision: https://phabricator.services.mozilla.com/D69717

docshell/base/BrowsingContext.cpp

@@ -1423,6 +1423,8 @@ nsresult BrowsingContext::LoadURI(nsDocShellLoadState* aLoadState,
     }
 
     if (ContentParent* cp = Canonical()->GetContentParent()) {
+      cp->TransmitBlobDataIfBlobURL(aLoadState->URI(),
+                                    aLoadState->TriggeringPrincipal());
       Unused << cp->SendLoadURI(this, aLoadState, aSetNavigating);
     }
   }

dom/ipc/ContentParent.cpp

@@ -5503,6 +5503,18 @@ void ContentParent::TransmitBlobURLsForPrincipal(nsIPrincipal* aPrincipal) {
   }
 }
 
+void ContentParent::TransmitBlobDataIfBlobURL(nsIURI* aURI,
+                                              nsIPrincipal* aPrincipal) {
+  MOZ_ASSERT(aURI);
+  MOZ_ASSERT(aPrincipal);
+
+  if (!IsBlobURI(aURI)) {
+    return;
+  }
+
+  TransmitBlobURLsForPrincipal(aPrincipal);
+}
+
 void ContentParent::EnsurePermissionsByKey(const nsCString& aKey,
                                            const nsCString& aOrigin) {
   // NOTE: Make sure to initialize the permission manager before updating the

dom/ipc/ContentParent.h

@@ -623,6 +623,19 @@ class ContentParent final
 
   nsresult TransmitPermissionsForPrincipal(nsIPrincipal* aPrincipal);
 
+  // This function is called in BrowsingContext immediately before IPC call to
+  // load a URI. If aURI is a BlobURL, this method transmits all BlobURLs for
+  // aPrincipal that were previously not transmitted. This allows for opening a
+  // locally created BlobURL in a new tab.
+  //
+  // The reason all previously untransmitted Blobs are transmitted is that the
+  // current BlobURL could contain html code, referring to another untransmitted
+  // BlobURL.
+  //
+  // Should eventually be made obsolete by broader design changes that only
+  // store BlobURLs in the parent process.
+  void TransmitBlobDataIfBlobURL(nsIURI* aURI, nsIPrincipal* aPrincipal);
+
   void OnCompositorDeviceReset() override;
 
   static hal::ProcessPriority GetInitialProcessPriority(Element* aFrameElement);