Fix a crash for ppb_pdf_impl.cc under single process model

components/pdf/renderer/ppb_pdf_impl.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 "components/pdf/renderer/ppb_pdf_impl.h"
 
 #include "base/files/scoped_file.h"
+#include "base/lazy_instance.h"
 #include "base/metrics/histogram.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/threading/thread_local.h"
 #include "build/build_config.h"
 #include "components/pdf/common/pdf_messages.h"
 #include "components/pdf/renderer/pdf_resource_util.h"
 #include "content/public/common/child_process_sandbox_support_linux.h"
 #include "content/public/common/referrer.h"
 #include "content/public/renderer/pepper_plugin_instance.h"
 #include "content/public/renderer/render_thread.h"
 #include "content/public/renderer/render_view.h"
 #include "gin/public/isolate_holder.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/private/ppb_pdf.h"
 #include "ppapi/c/trusted/ppb_browser_font_trusted.h"
 #include "ppapi/shared_impl/ppapi_globals.h"
 #include "ppapi/shared_impl/resource.h"
 #include "ppapi/shared_impl/resource_tracker.h"
 #include "ppapi/shared_impl/var.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebElement.h"
 #include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebPluginContainer.h"
 #include "third_party/WebKit/public/web/WebView.h"
 #include "third_party/icu/source/i18n/unicode/usearch.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
 namespace pdf {
 namespace {
 
-PPB_PDF_Impl::PrintClient* g_print_client = NULL;
+// --single-process model may fail in CHECK(!g_print_client) if there exist
+// more than two RenderThreads, so here we use TLS for g_print_client.
+// See http://crbug.com/457580.
+base::LazyInstance<base::ThreadLocalPointer<PPB_PDF_Impl::PrintClient> >::Leaky
+    g_print_client_tls = LAZY_INSTANCE_INITIALIZER;
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID)
 class PrivateFontFile : public ppapi::Resource {
  public:
   PrivateFontFile(PP_Instance instance, int fd)
       : Resource(ppapi::OBJECT_IS_IMPL, instance), fd_(fd) {}
 
   bool GetFontTable(uint32_t table, void* output, uint32_t* output_length) {
     size_t temp_size = static_cast<size_t>(*output_length);
     bool rv = content::GetFontTable(fd_.get(),
@@ skipping 201 matching lines @@
 
 void Print(PP_Instance instance) {
   PPB_PDF_Impl::InvokePrintingForInstance(instance);
 }
 
 PP_Bool IsFeatureEnabled(PP_Instance instance, PP_PDFFeature feature) {
   switch (feature) {
     case PP_PDFFEATURE_HIDPI:
       return PP_TRUE;
     case PP_PDFFEATURE_PRINTING:
-      return (g_print_client && g_print_client->IsPrintingEnabled(instance))
+      return (g_print_client_tls.Pointer()->Get() &&
+              g_print_client_tls.Pointer()->Get()->IsPrintingEnabled(instance))
                  ? PP_TRUE
                  : PP_FALSE;
   }
   return PP_FALSE;
 }
 
 PP_Resource GetResourceImageForScale(PP_Instance instance_id,
                                      PP_ResourceImage image_id,
                                      float scale) {
   // Validate the instance.
@@ skipping 93 matching lines @@
 
 }  // namespace
 
 // static
 const PPB_PDF* PPB_PDF_Impl::GetInterface() {
   return &ppb_pdf;
 }
 
 // static
 bool PPB_PDF_Impl::InvokePrintingForInstance(PP_Instance instance_id) {
-  return g_print_client ? g_print_client->Print(instance_id) : false;
+  return g_print_client_tls.Pointer()->Get()
+             ? g_print_client_tls.Pointer()->Get()->Print(instance_id)
+             : false;
 }
 
 void PPB_PDF_Impl::SetPrintClient(PPB_PDF_Impl::PrintClient* client) {
-  CHECK(!g_print_client) << "There should only be a single PrintClient.";
-  g_print_client = client;
+  CHECK(!g_print_client_tls.Pointer()->Get())
+      << "There should only be a single PrintClient for one RenderThread.";
+  g_print_client_tls.Pointer()->Set(client);
 }
 
 }  // namespace pdf