feat: enable pdf viewer (#21794)

shell/browser/plugins/plugin_utils.cc

@@ -0,0 +1,63 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "shell/browser/plugins/plugin_utils.h"
+
+#include <vector>
+
+#include "base/values.h"
+#include "content/public/common/webplugininfo.h"
+#include "extensions/buildflags/buildflags.h"
+#include "url/gurl.h"
+#include "url/origin.h"
+
+#if BUILDFLAG(ENABLE_EXTENSIONS)
+#include "extensions/browser/extension_registry.h"
+#include "extensions/browser/extension_util.h"
+#include "extensions/common/constants.h"
+#include "extensions/common/extension.h"
+#include "extensions/common/manifest_handlers/mime_types_handler.h"
+#endif
+
+// static
+std::string PluginUtils::GetExtensionIdForMimeType(
+    content::BrowserContext* browser_context,
+    const std::string& mime_type) {
+  auto map = GetMimeTypeToExtensionIdMap(browser_context);
+  auto it = map.find(mime_type);
+  if (it != map.end())
+    return it->second;
+  return std::string();
+}
+
+base::flat_map<std::string, std::string>
+PluginUtils::GetMimeTypeToExtensionIdMap(
+    content::BrowserContext* browser_context) {
+  base::flat_map<std::string, std::string> mime_type_to_extension_id_map;
+#if BUILDFLAG(ENABLE_EXTENSIONS)
+  std::vector<std::string> whitelist = MimeTypesHandler::GetMIMETypeWhitelist();
+  // Go through the white-listed extensions and try to use them to intercept
+  // the URL request.
+  for (const std::string& extension_id : whitelist) {
+    const extensions::Extension* extension =
+        extensions::ExtensionRegistry::Get(browser_context)
+            ->enabled_extensions()
+            .GetByID(extension_id);
+    // The white-listed extension may not be installed, so we have to nullptr
+    // check |extension|.
+    if (!extension) {
+      continue;
+    }
+
+    if (MimeTypesHandler* handler = MimeTypesHandler::GetHandler(extension)) {
+      for (const auto& supported_mime_type : handler->mime_type_set()) {
+        DCHECK(!base::Contains(mime_type_to_extension_id_map,
+                               supported_mime_type));
+        mime_type_to_extension_id_map[supported_mime_type] = extension_id;
+      }
+    }
+  }
+#endif
+  return mime_type_to_extension_id_map;
+}