Remove GetInitiatorSchemeBypassingDocumentBlocking.

This CL removes the GetInitiatorSchemeBypassingDocumentBlocking method
from ContentBrowserClient.

This method used to be called by implementation of Cross-Origin Read
Blocking (CORB) before NetworkService shipped.  This dependency is gone
now.

Before this CL, the only remaining caller of this method was
AppCacheSubresourceURLFactory::CreateLoaderAndStart.  The method was
called to exclude content script requests from request_initiator checks
(this exclusion was introduced in r624685).  Such exclusion is no longer
needed, after request_initiator=website (see r694827 and r710554).

Bug: 940068
Change-Id: I736f1414ffe890da9cd6477d377f4482168befae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1926541Reviewed-by: Charlie Reis <creis@chromium.org>
Commit-Queue: Łukasz Anforowicz <lukasza@chromium.org>
Cr-Commit-Position: refs/heads/master@{#724030}

chrome/browser/chrome_content_browser_client.cc

@@ -1603,21 +1603,6 @@ bool ChromeContentBrowserClient::ShouldLockToOrigin(
   return true;
 }
 
-const char*
-ChromeContentBrowserClient::GetInitiatorSchemeBypassingDocumentBlocking() {
-#if BUILDFLAG(ENABLE_EXTENSIONS)
-  // Don't block responses for extension processes or for content scripts.
-  // TODO(creis): When every extension fetch (including content scripts) has
-  // been made to go through an extension-specific URLLoaderFactory, this
-  // mechanism ought to work by enumerating the host permissions from the
-  // extension manifest, and forwarding them on to the network service while
-  // brokering the URLLoaderFactory.
-  return extensions::kExtensionScheme;
-#else
-  return nullptr;
-#endif
-}
-
 bool ChromeContentBrowserClient::ShouldTreatURLSchemeAsFirstPartyWhenTopLevel(
     base::StringPiece scheme,
     bool is_embedded_origin_secure) {

chrome/browser/chrome_content_browser_client.h

@@ -150,7 +150,6 @@ class ChromeContentBrowserClient : public content::ContentBrowserClient {
                                        const GURL& effective_site_url) override;
   bool ShouldLockToOrigin(content::BrowserContext* browser_context,
                           const GURL& effective_site_url) override;
-  const char* GetInitiatorSchemeBypassingDocumentBlocking() override;
   bool ShouldTreatURLSchemeAsFirstPartyWhenTopLevel(
       base::StringPiece scheme,
       bool is_embedded_origin_secure) override;

content/browser/appcache/appcache_subresource_url_factory.cc

@@ -384,21 +384,14 @@ void AppCacheSubresourceURLFactory::CreateLoaderAndStart(
       !policy->CanAccessDataForOrigin(appcache_host_->process_id(),
                                       request.request_initiator.value()) &&
       policy->HasSecurityState(appcache_host_->process_id())) {
-    const char* scheme_exception =
-        GetContentClient()
-            ->browser()
-            ->GetInitiatorSchemeBypassingDocumentBlocking();
-    if (!scheme_exception ||
-        request.request_initiator.value().scheme() != scheme_exception) {
-      static auto* initiator_origin_key = base::debug::AllocateCrashKeyString(
-          "initiator_origin", base::debug::CrashKeySize::Size64);
-      base::debug::SetCrashKeyString(
-          initiator_origin_key, request.request_initiator.value().Serialize());
-
-      mojo::ReportBadMessage(
-          "APPCACHE_SUBRESOURCE_URL_FACTORY_INVALID_INITIATOR");
-      return;
-    }
+    static auto* initiator_origin_key = base::debug::AllocateCrashKeyString(
+        "initiator_origin", base::debug::CrashKeySize::Size64);
+    base::debug::SetCrashKeyString(
+        initiator_origin_key, request.request_initiator.value().Serialize());
+
+    mojo::ReportBadMessage(
+        "APPCACHE_SUBRESOURCE_URL_FACTORY_INVALID_INITIATOR");
+    return;
   }
 
   // Subresource requests from renderer processes should not be allowed to use

content/public/browser/content_browser_client.cc

@@ -129,11 +129,6 @@ bool ContentBrowserClient::ShouldLockToOrigin(BrowserContext* browser_context,
   return true;
 }
 
-const char*
-ContentBrowserClient::GetInitiatorSchemeBypassingDocumentBlocking() {
-  return nullptr;
-}
-
 bool ContentBrowserClient::ShouldTreatURLSchemeAsFirstPartyWhenTopLevel(
     base::StringPiece scheme,
     bool is_embedded_origin_secure) {

content/public/browser/content_browser_client.h

@@ -330,11 +330,6 @@ class CONTENT_EXPORT ContentBrowserClient {
   virtual bool ShouldLockToOrigin(BrowserContext* browser_context,
                                   const GURL& effective_url);
 
-  // Returns the scheme of request initiator that should be ignored by
-  // cross-origin read blocking.  nullptr can be returned to indicate that no
-  // exceptions should be granted based on initiator's scheme.
-  virtual const char* GetInitiatorSchemeBypassingDocumentBlocking();
-
   // Returns true if everything embedded inside a document with given scheme
   // should be treated as first-party content. |scheme| will be in canonical
   // (lowercased) form. |is_embedded_origin_secure| refers to whether the origin