Shared Storage: We reject promises when Shared Storage is disabled.

We hook up the permission check method
`privacy_sandbox_settings::IsSharedStorageAllowed()`. This involves
changing the mojo interface for `SharedStorageDocumentService`.

We also add some test utils in content/public/test/ to make it possible
to test at the chrome/ layer, and export
`SharedStorageDocumentServiceImpl` to make it visible to these test
utils in component builds.

Bug: 1325020,1218540
Change-Id: Iaa2f1e71c2e6fc99764212c6a9e9299c218a6062
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3612224
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Cammie Smith Barnes <cammie@chromium.org>
Reviewed-by: Ayu Ishii <ayui@chromium.org>
Reviewed-by: Yao Xiao <yaoxia@chromium.org>
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1002891}

chrome/browser/chrome_content_browser_client.cc

@@ -2898,6 +2898,19 @@ bool ChromeContentBrowserClient::IsConversionMeasurementOperationAllowed(
   }
 }
 
+bool ChromeContentBrowserClient::IsSharedStorageAllowed(
+    content::BrowserContext* browser_context,
+    const url::Origin& top_frame_origin,
+    const url::Origin& accessing_origin) {
+  Profile* profile = Profile::FromBrowserContext(browser_context);
+  auto* privacy_sandbox_settings =
+      PrivacySandboxSettingsFactory::GetForProfile(profile);
+  DCHECK(privacy_sandbox_settings);
+
+  return privacy_sandbox_settings->IsSharedStorageAllowed(top_frame_origin,
+                                                          accessing_origin);
+}
+
 #if BUILDFLAG(IS_CHROMEOS)
 void ChromeContentBrowserClient::OnTrustAnchorUsed(
     content::BrowserContext* browser_context) {

chrome/browser/chrome_content_browser_client.h

@@ -301,6 +301,9 @@ class ChromeContentBrowserClient : public content::ContentBrowserClient {
       const url::Origin* impression_origin,
       const url::Origin* conversion_origin,
       const url::Origin* reporting_origin) override;
+  bool IsSharedStorageAllowed(content::BrowserContext* browser_context,
+                              const url::Origin& top_frame_origin,
+                              const url::Origin& accessing_origin) override;
 #if BUILDFLAG(IS_CHROMEOS)
   void OnTrustAnchorUsed(content::BrowserContext* browser_context) override;
 #endif