Convert the async device ID getter to a chrome resource host

chrome/browser/renderer_host/pepper/pepper_flash_device_id_host.cc

+// Copyright (c) 2012 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 "chrome/browser/renderer_host/pepper/pepper_flash_device_id_host.h"
+
+#include "base/bind.h"
+#include "base/compiler_specific.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "content/public/browser/browser_context.h"
+#include "content/public/browser/browser_ppapi_host.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/render_view_host.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/host/dispatch_host_message.h"
+#include "ppapi/host/host_message_context.h"
+#include "ppapi/host/ppapi_host.h"
+#include "ppapi/proxy/ppapi_messages.h"
+
+using content::BrowserPpapiHost;
+using content::BrowserThread;
+
+namespace chrome {
+
+namespace {
+
+// The path to the file containing the DRM ID.
+// It is mirrored from
+//   chrome/browser/chromeos/system/drm_settings.cc
+const char kDRMIdentifierFile[] = "Pepper DRM ID.0";
+
+}  // namespace
+
+// PepperFlashDeviceIDHost::Fetcher --------------------------------------------
+
+PepperFlashDeviceIDHost::Fetcher::Fetcher(
+    const base::WeakPtr<PepperFlashDeviceIDHost>& host)
+    : host_(host) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+}
+
+PepperFlashDeviceIDHost::Fetcher::~Fetcher() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+}
+
+void PepperFlashDeviceIDHost::Fetcher::Start(BrowserPpapiHost* browser_host) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  int process_id = 0;
+  int view_id = 0;
+  browser_host->GetRenderViewIDsForInstance(host_->pp_instance(),
+                                            &process_id,
+                                            &view_id);
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&PepperFlashDeviceIDHost::Fetcher::GetFilePathOnUIThread,
+                 this, process_id, view_id));
+}
+
+void PepperFlashDeviceIDHost::Fetcher::GetFilePathOnUIThread(
+    int render_process_id,
+    int render_view_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  FilePath path;
+  content::RenderViewHost* render_view_host =
+      content::RenderViewHost::FromID(render_process_id, render_view_id);
+  if (render_view_host) {
+    content::BrowserContext* browser_context =
+        render_view_host->GetProcess()->GetBrowserContext();
+    // Don't use DRM IDs when incognito to prevent tracking.
+    if (!browser_context->IsOffTheRecord())
+      path = browser_context->GetPath().AppendASCII(kDRMIdentifierFile);
+  }
+
+  // Continue on the file thread (on failure/incognito, this will just send
+  // the empty path which will forward the error).
+  BrowserThread::PostTask(
+      BrowserThread::FILE, FROM_HERE,
+      base::Bind(&PepperFlashDeviceIDHost::Fetcher::ReadDRMFileOnFileThread,
+                 this, path));
+}
+
+void PepperFlashDeviceIDHost::Fetcher::ReadDRMFileOnFileThread(
+    const FilePath& path) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+
+  std::string contents;
+  if (!path.empty())
+    file_util::ReadFileToString(path, &contents);
+
+  // Give back to the resource host on the IO thread. On failure this will just
+  // forward the empty string.
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&PepperFlashDeviceIDHost::Fetcher::ReplyOnIOThread,
+                 this, contents));
+}
+
+void PepperFlashDeviceIDHost::Fetcher::ReplyOnIOThread(
+    const std::string& contents) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  if (host_.get())  // Plugin or resource could have been deleted.
+    host_->GotDRMContents(contents);
+}
+
+// PepperFlashDeviceIDHost -----------------------------------------------------
+
+PepperFlashDeviceIDHost::PepperFlashDeviceIDHost(BrowserPpapiHost* host,
+                                                 PP_Instance instance,
+                                                 PP_Resource resource)
+    : ppapi::host::ResourceHost(host->GetPpapiHost(), instance, resource),
+      factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)),
+      browser_ppapi_host_(host) {
+}
+
+PepperFlashDeviceIDHost::~PepperFlashDeviceIDHost() {
+}
+
+int32_t PepperFlashDeviceIDHost::OnResourceMessageReceived(
+    const IPC::Message& msg,
+    ppapi::host::HostMessageContext* context) {
+  IPC_BEGIN_MESSAGE_MAP(PepperFlashDeviceIDHost, msg)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_FlashDeviceID_GetDeviceID,
+                                        OnHostMsgGetDeviceID)
+  IPC_END_MESSAGE_MAP()
+  return PP_ERROR_FAILED;
+}
+
+int32_t PepperFlashDeviceIDHost::OnHostMsgGetDeviceID(
+    const ppapi::host::HostMessageContext* context) {
+  if (fetcher_)
+    return PP_ERROR_INPROGRESS;
+
+  fetcher_ = new Fetcher(factory_.GetWeakPtr());
+  fetcher_->Start(browser_ppapi_host_);
+  reply_params_ = context->MakeReplyParams();
+  return PP_OK_COMPLETIONPENDING;
+}
+
+void PepperFlashDeviceIDHost::GotDRMContents(const std::string& contents) {
+  fetcher_ = NULL;
+  reply_params_.set_result(contents.empty() ? PP_ERROR_FAILED : PP_OK);
+  host()->SendReply(reply_params_,
+                    PpapiPluginMsg_FlashDeviceID_GetDeviceIDReply(contents));
+}
+
+}  // namespace chrome