Extensions: Send the tab id to platform apps.

chrome/browser/extensions/api/media_galleries/media_galleries_api.cc

Index: chrome/browser/extensions/api/media_galleries/media_galleries_api.cc
===================================================================
--- chrome/browser/extensions/api/media_galleries/media_galleries_api.cc	(revision 246091)
+++ chrome/browser/extensions/api/media_galleries/media_galleries_api.cc	(working copy)
@@ -19,8 +19,10 @@
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/api/file_system/file_system_api.h"
+#include "chrome/browser/extensions/api/messaging/message_service.h"
 #include "chrome/browser/extensions/blob_reader.h"
 #include "chrome/browser/extensions/extension_prefs.h"
+#include "chrome/browser/extensions/extension_tab_util.h"
 #include "chrome/browser/media_galleries/media_file_system_registry.h"
 #include "chrome/browser/media_galleries/media_galleries_dialog_controller.h"
 #include "chrome/browser/media_galleries/media_galleries_histograms.h"
@@ -403,17 +405,39 @@
 
 bool MediaGalleriesAddUserSelectedFolderFunction::RunImpl() {
   media_galleries::UsageCount(media_galleries::ADD_USER_SELECTED_FOLDER);
+
+  // Need to do this before OnPreferencesInit() because OnPreferencesInit() can
+  // be deferred, by which time, extensions::MessageService() no longer knows
+  // whether this API can access the source tab or not.

[not at google - send to devlin, 2014/01/23 16:41:59]

I'm being dense and can't follow why this (and the corresponding
CanPlatformAppAccessTab method) is needed. Is it so that the browser doesn't
need to trust what the renderer says re tab ID or something? If it is that... I
wouldn't worry about it, we already trust the information about the sender
extension ID.

[Lei Zhang, 2014/01/23 20:53:12]

Yes, I'm being paranoid, but if you say we don't need it, I'll remove it.

[not at google - send to devlin, 2014/01/23 21:07:43]

Thanks for being paranoid. The bug, if it can be called that, with the extension
ID may be worth fixing at some point; and it would make sense to include the
source tab ID information with that.

So long as it's C++ not JS making the decisions on the renderer I'm ok with it
though. JS is a different story. Never trust.

+  bool can_access_source_tab = false;
+  if (source_tab_id() >= 0) {
+    Profile* profile = GetProfile();
+    can_access_source_tab =
+        extensions::MessageService::Get(profile)->CanPlatformAppAccessTab(
+            GetExtension()->id(), source_tab_id());
+  }
   return Setup(GetProfile(), &error_, base::Bind(
-      &MediaGalleriesAddUserSelectedFolderFunction::OnPreferencesInit, this));
+      &MediaGalleriesAddUserSelectedFolderFunction::OnPreferencesInit,
+      this,
+      can_access_source_tab));
 }
 
-void MediaGalleriesAddUserSelectedFolderFunction::OnPreferencesInit() {
+void MediaGalleriesAddUserSelectedFolderFunction::OnPreferencesInit(
+    bool can_access_source_tab) {
   Profile* profile = GetProfile();
   const std::string& app_id = GetExtension()->id();
   WebContents* contents = GetWebContents(render_view_host(), profile, app_id);
   if (!contents) {
-    SendResponse(false);
-    return;
+    bool found_tab = false;
+    if (can_access_source_tab) {
+      found_tab = extensions::ExtensionTabUtil::GetTabById(
+          source_tab_id(), profile, profile->IsOffTheRecord(),
+          NULL, NULL, &contents, NULL);
+    }
+    if (!found_tab || !contents) {
+      SendResponse(false);
+      return;
+    }
   }
 
   if (!user_gesture()) {