Ensuring interception of stream get determined by plugin path before checking mime type.

chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc

Index: chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
diff --git a/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc b/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
index 715ddcc62053273747a7998fc15493a582518051..1ba05898127ab5f7b87a36c49f45ab17ab8ad2af 100644
--- a/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
+++ b/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
@@ -210,36 +210,6 @@ void SendExecuteMimeTypeHandlerEvent(scoped_ptr<content::StreamInfo> stream,
       extension_id, web_contents, stream.Pass(), view_id, expected_content_size,
       embedded, render_process_id, render_frame_id);
 }
-
-// TODO(raymes): This won't return the right result if plugins haven't been
-// loaded yet. Fixing this properly really requires fixing crbug.com/443466.
-bool IsPluginEnabledForExtension(const Extension* extension,
-                                 const ResourceRequestInfo* info,
-                                 const std::string& mime_type,
-                                 const GURL& url) {
-  content::PluginService* service = content::PluginService::GetInstance();
-  std::vector<content::WebPluginInfo> plugins;
-  service->GetPluginInfoArray(url, mime_type, true, &plugins, nullptr);
-  content::PluginServiceFilter* filter = service->GetFilter();
-
-  for (auto& plugin : plugins) {
-    // Check that the plugin is running the extension.
-    if (plugin.path !=
-        base::FilePath::FromUTF8Unsafe(extension->url().spec())) {
-      continue;
-    }
-    // Check that the plugin is actually enabled.
-    if (!filter || filter->IsPluginAvailable(info->GetChildID(),
-                                             info->GetRenderFrameID(),
-                                             info->GetContext(),
-                                             url,
-                                             GURL(),
-                                             &plugin)) {
-      return true;
-    }
-  }
-  return false;
-}
 #endif  // !defined(ENABLE_EXTENSIONS)
 
 #if !defined(OS_ANDROID)
@@ -628,6 +598,7 @@ bool ChromeResourceDispatcherHostDelegate::ShouldForceDownloadResource(
 }
 
 bool ChromeResourceDispatcherHostDelegate::ShouldInterceptResourceAsStream(
+    const base::FilePath& file_path,

[raymes, 2015/03/12 05:21:03]

plugin_path

     net::URLRequest* request,
     const std::string& mime_type,
     GURL* origin,
@@ -640,6 +611,9 @@ bool ChromeResourceDispatcherHostDelegate::ShouldInterceptResourceAsStream(
   const scoped_refptr<const extensions::InfoMap> extension_info_map(
       io_data->GetExtensionInfoMap());
   std::vector<std::string> whitelist = MimeTypesHandler::GetMIMETypeWhitelist();
+
+  content::PluginService* service = content::PluginService::GetInstance();
+  content::PluginServiceFilter* filter = service->GetFilter();

[raymes, 2015/03/12 05:21:03]

We can remove the above 2 lines (see below)

   // Go through the white-listed extensions and try to use them to intercept
   // the URL request.
   for (size_t i = 0; i < whitelist.size(); ++i) {
@@ -654,24 +628,39 @@ bool ChromeResourceDispatcherHostDelegate::ShouldInterceptResourceAsStream(
       continue;
     }
 
-    MimeTypesHandler* handler = MimeTypesHandler::GetHandler(extension);
-    if (handler && handler->CanHandleMIMEType(mime_type)) {
+    if (file_path == base::FilePath::FromUTF8Unsafe(extension->url().spec())) {
       StreamTargetInfo target_info;
       *origin = Extension::GetBaseURLFromExtensionId(extension_id);
       target_info.extension_id = extension_id;
-      if (!handler->handler_url().empty()) {
-        // This is reached in the case of MimeHandlerViews. If the
-        // MimeHandlerView plugin is disabled, then we shouldn't intercept the
-        // stream.
-        if (!IsPluginEnabledForExtension(extension, info, mime_type,
-                                         request->url())) {
+
+      content::WebPluginInfo plugin;
+      bool plugin_info = service->GetPluginInfoByPath(file_path, &plugin);
+      // Check that the plugin is actually enabled.

[raymes, 2015/03/12 05:21:03]

We don't need to check if it's enabled. This check will already be performed
before we get here. We can delete this.

+      // MimeHandlerView plugin is disabled, then we shouldn't intercept the
+      // stream.
+      if (!plugin_info && filter &&
+          !filter->IsPluginAvailable(
+              info->GetChildID(), info->GetRenderFrameID(), info->GetContext(),
+              request->url(), GURL(), &plugin)) {
           continue;
-        }
-        target_info.view_id = base::GenerateGUID();
-        *payload = target_info.view_id;
       }

[raymes, 2015/03/12 05:21:03]

I think we can add a DCHECK in this case:
DCHECK(!handler->handler_url().empty());

+      target_info.view_id = base::GenerateGUID();
+      *payload = target_info.view_id;
       stream_target_info_[request] = target_info;
       return true;
+    } else {
+      MimeTypesHandler* handler = MimeTypesHandler::GetHandler(extension);
+      if (handler && handler->CanHandleMIMEType(mime_type)) {
+        StreamTargetInfo target_info;
+        *origin = Extension::GetBaseURLFromExtensionId(extension_id);
+        target_info.extension_id = extension_id;
+        if (!handler->handler_url().empty()) {

[raymes, 2015/03/12 05:21:03]

In this case we should be able to remove this if-statement and turn it into the
opposite DCHECK:
DCHECK(handler->handler_url().empty());

+          target_info.view_id = base::GenerateGUID();
+          *payload = target_info.view_id;

[raymes, 2015/03/12 05:21:03]

We can remove the above 2 lines here, they should never be hit.

+        }
+        stream_target_info_[request] = target_info;
+        return true;
+      }
     }
   }
 #endif