Avoid sync IPCs for FileSystem API

chrome/renderer/content_settings_observer.cc

Index: chrome/renderer/content_settings_observer.cc
diff --git a/chrome/renderer/content_settings_observer.cc b/chrome/renderer/content_settings_observer.cc
index f5489a07f70d2ccaa399358f20f14dfad50041af..4953b6aea77602591c2ebb137e06445727b9ecec 100644
--- a/chrome/renderer/content_settings_observer.cc
+++ b/chrome/renderer/content_settings_observer.cc
@@ -15,6 +15,7 @@
 #include "content/public/renderer/render_frame.h"
 #include "content/public/renderer/render_view.h"
 #include "extensions/common/constants.h"
+#include "third_party/WebKit/public/platform/WebPermissionCallbacks.h"
 #include "third_party/WebKit/public/platform/WebURL.h"
 #include "third_party/WebKit/public/web/WebDataSource.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
@@ -28,6 +29,7 @@ using blink::WebDataSource;
 using blink::WebDocument;
 using blink::WebFrame;
 using blink::WebFrameClient;
+using blink::WebPermissionCallbacks;
 using blink::WebSecurityOrigin;
 using blink::WebString;
 using blink::WebURL;
@@ -153,7 +155,8 @@ ContentSettingsObserver::ContentSettingsObserver(
       allow_running_insecure_content_(false),
       content_setting_rules_(NULL),
       is_interstitial_page_(false),
-      npapi_plugins_blocked_(false) {
+      npapi_plugins_blocked_(false),
+      current_request_id_(0) {
   ClearBlockedContentSettings();
   render_frame->GetWebFrame()->setPermissionClient(this);
 }
@@ -194,6 +197,8 @@ bool ContentSettingsObserver::OnMessageReceived(const IPC::Message& message) {
     IPC_MESSAGE_HANDLER(ChromeViewMsg_SetAllowRunningInsecureContent,
                         OnSetAllowRunningInsecureContent)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_ReloadFrame, OnReloadFrame);
+    IPC_MESSAGE_HANDLER(ChromeViewMsg_RequestFileSystemAccessResponse,
+                        OnRequestFileSystemAccessResponse)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   if (handled)
@@ -261,6 +266,30 @@ bool ContentSettingsObserver::allowFileSystem(WebFrame* frame) {
   return result;
 }
 
+void ContentSettingsObserver::requestFileSystemAccess(
+    WebFrame* frame, const WebPermissionCallbacks& callbacks) {
+  ++current_request_id_;
+  std::pair<PermissionRequestMap::iterator, bool> insert_result =
+      permission_requests_.insert(
+          std::make_pair(current_request_id_, callbacks));
+
+  // Verify there are no duplicate insertions.
+  DCHECK(insert_result.second);
+
+  if (frame->document().securityOrigin().isUnique() ||
+      frame->top()->document().securityOrigin().isUnique()) {
+    insert_result.first->second.doDeny();
+    permission_requests_.erase(insert_result.first);

[kinuko, 2014/03/07 08:22:29]

I feel this could be checked before you insert the callbacks to the internal
map?  Also I don't feel using insert_result here is particularly useful while
it's losing some readability. Probably this could be written w/o typing lengthy
type names like:

if (...unique) {
  callbacks.doDeny();
  return;
}

bool inserted = requests_.insert(id, callbacks).second;
DCHECK(inserted);

Send(...);

+    return;
+  }
+
+  Send(new ChromeViewHostMsg_RequestFileSystemAccess(
+      routing_id(),
+      current_request_id_,
+      GURL(frame->document().securityOrigin().toString()),
+      GURL(frame->top()->document().securityOrigin().toString())));
+}
+
 bool ContentSettingsObserver::allowImage(WebFrame* frame,
                                          bool enabled_per_settings,
                                          const WebURL& image_url) {
@@ -589,6 +618,22 @@ void ContentSettingsObserver::OnReloadFrame() {
   render_frame()->GetWebFrame()->reload();
 }
 
+void ContentSettingsObserver::OnRequestFileSystemAccessResponse(int request_id,
+                                                                bool allowed) {
+  PermissionRequestMap::iterator it = permission_requests_.find(request_id);
+  if (it == permission_requests_.end())
+    return;
+
+  WebPermissionCallbacks callbacks = it->second;
+  permission_requests_.erase(it);
+
+  if (allowed) {
+    callbacks.doAllow();
+    return;
+  }
+  callbacks.doDeny();
+}
+
 void ContentSettingsObserver::ClearBlockedContentSettings() {
   for (size_t i = 0; i < arraysize(content_blocked_); ++i)
     content_blocked_[i] = false;