Fix crash when displaying system print dialog on Linux.

chrome/browser/printing/printing_message_filter.cc

Index: chrome/browser/printing/printing_message_filter.cc
diff --git a/chrome/browser/printing/printing_message_filter.cc b/chrome/browser/printing/printing_message_filter.cc
index a100d44db5e1b680e00cbd84eb5d16ec23568880..c392979b9433fdfa9bb8757bf7437bf118efdb23 100644
--- a/chrome/browser/printing/printing_message_filter.cc
+++ b/chrome/browser/printing/printing_message_filter.cc
@@ -13,6 +13,9 @@
 #include "chrome/browser/printing/print_job_manager.h"
 #include "chrome/browser/ui/webui/print_preview/print_preview_ui.h"
 #include "chrome/common/print_messages.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_view.h"
 
 #if defined(OS_CHROMEOS)
 #include <fcntl.h>
@@ -22,9 +25,6 @@
 #include "base/file_util.h"
 #include "base/lazy_instance.h"
 #include "chrome/browser/printing/print_dialog_cloud.h"
-#include "content/public/browser/render_view_host.h"
-#include "content/public/browser/web_contents.h"
-#include "content/public/browser/web_contents_view.h"
 #endif
 
 using content::BrowserThread;
@@ -90,9 +90,10 @@ PrintingMessageFilter::~PrintingMessageFilter() {
 void PrintingMessageFilter::OverrideThreadForMessage(
     const IPC::Message& message, BrowserThread::ID* thread) {
 #if defined(OS_CHROMEOS)
-  if (message.type() == PrintHostMsg_AllocateTempFileForPrinting::ID ||
-      message.type() == PrintHostMsg_TempFileForPrintingWritten::ID) {
+  if (message.type() == PrintHostMsg_AllocateTempFileForPrinting::ID) {
     *thread = BrowserThread::FILE;
+  } else if (message.type() == PrintHostMsg_TempFileForPrintingWritten::ID) {
+    *thread = BrowserThread::UI;
   }
 #endif
 }
@@ -161,7 +162,7 @@ void PrintingMessageFilter::OnAllocateTempFileForPrinting(
 
 void PrintingMessageFilter::OnTempFileForPrintingWritten(int render_view_id,
                                                          int sequence_number) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));

[Lei Zhang, 2012/06/11 23:32:28]

If you do this, then |g_printing_file_descriptor_map| needs locking.

Do we have to do this on the UI thread? How did CrOS get away with calling the
same methods from the FILE thread?

[Albert Bodenhamer, 2012/06/11 23:54:58]

Argh!  Yeah.  I should have caught that.

CrOS DIDN'T get away with calling this on the FILE thread. 
WebContents::FromRenderViewHost was DCHECKing because it wasn't called from the
UI thread.  It only ever worked because it used to use BrowserList.

I'll need to call it from the FILE thread and then post a task to the UI thread
to finish the job.  Thankfully CreatePrintDialogForFile can be called from the
UI thread so it's not too complicated.

On 2012/06/11 23:32:28, Lei Zhang wrote:

[Albert Bodenhamer, 2012/06/12 01:19:02]

Done.

   SequenceToPathMap* map = &g_printing_file_descriptor_map.Get().map;
   SequenceToPathMap::iterator it = map->find(sequence_number);
   if (it == map->end()) {
@@ -169,10 +170,7 @@ void PrintingMessageFilter::OnTempFileForPrintingWritten(int render_view_id,
                     "renderer: " << sequence_number;
     return;
   }
-
-  content::RenderViewHost* view = content::RenderViewHost::FromID(
-      render_process_id_, render_view_id);
-  content::WebContents* wc = content::WebContents::FromRenderViewHost(view);
+  content::WebContents* wc = GetWebContentsForRenderView(render_view_id);
   print_dialog_cloud::CreatePrintDialogForFile(
       wc->GetBrowserContext(),
       wc->GetView()->GetTopLevelNativeWindow(),
@@ -187,25 +185,57 @@ void PrintingMessageFilter::OnTempFileForPrintingWritten(int render_view_id,
 }
 #endif  // defined(OS_CHROMEOS)
 
-void PrintingMessageFilter::OnGetDefaultPrintSettings(IPC::Message* reply_msg) {
+content::WebContents* PrintingMessageFilter::GetWebContentsForRenderView(
+    int render_view_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  content::RenderViewHost* view = content::RenderViewHost::FromID(
+      render_process_id_, render_view_id);
+  return content::WebContents::FromRenderViewHost(view);
+}
+
+void PrintingMessageFilter::GetPrintSettingsForRenderView(
+    int render_view_id,
+    GetPrintSettingsForRenderViewParams params,
+    const base::Closure& callback,
+    scoped_refptr<printing::PrinterQuery> printer_query) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  content::WebContents* wc = GetWebContentsForRenderView(render_view_id);
+
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&printing::PrinterQuery::GetSettings, printer_query,
+                 params.ask_user_for_settings, wc->GetView()->GetNativeView(),
+                 params.expected_page_count, params.has_selection,
+                 params.margin_type, callback));
+}
+
+void PrintingMessageFilter::OnGetDefaultPrintSettings(
+    IPC::Message* reply_msg) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   scoped_refptr<printing::PrinterQuery> printer_query;
   if (!print_job_manager_->printing_enabled()) {
     // Reply with NULL query.
     OnGetDefaultPrintSettingsReply(printer_query, reply_msg);
     return;
   }
-
   print_job_manager_->PopPrinterQuery(0, &printer_query);
   if (!printer_query.get())
     printer_query = new printing::PrinterQuery;
 
   // Loads default settings. This is asynchronous, only the IPC message sender
   // will hang until the settings are retrieved.
-  printer_query->GetSettings(
-      printing::PrinterQuery::DEFAULTS, NULL, 0, false,
-      printing::DEFAULT_MARGINS,
-      base::Bind(&PrintingMessageFilter::OnGetDefaultPrintSettingsReply, this,
-                 printer_query, reply_msg));
+  GetPrintSettingsForRenderViewParams params;
+  params.ask_user_for_settings = printing::PrinterQuery::DEFAULTS;
+  params.expected_page_count = 0;
+  params.has_selection = false;
+  params.margin_type = printing::DEFAULT_MARGINS;
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&PrintingMessageFilter::GetPrintSettingsForRenderView, this,
+          reply_msg->routing_id(), params,
+          base::Bind(&PrintingMessageFilter::OnGetDefaultPrintSettingsReply,
+              this, printer_query, reply_msg),
+          printer_query));
 }
 
 void PrintingMessageFilter::OnGetDefaultPrintSettingsReply(
@@ -235,20 +265,24 @@ void PrintingMessageFilter::OnGetDefaultPrintSettingsReply(
 void PrintingMessageFilter::OnScriptedPrint(
     const PrintHostMsg_ScriptedPrint_Params& params,
     IPC::Message* reply_msg) {
-  gfx::NativeView host_view =
-      gfx::NativeViewFromIdInBrowser(params.host_window_id);
-
   scoped_refptr<printing::PrinterQuery> printer_query;
   print_job_manager_->PopPrinterQuery(params.cookie, &printer_query);
   if (!printer_query.get()) {
     printer_query = new printing::PrinterQuery;
   }
-
-  printer_query->GetSettings(
-      printing::PrinterQuery::ASK_USER, host_view, params.expected_pages_count,
-      params.has_selection, params.margin_type,
-      base::Bind(&PrintingMessageFilter::OnScriptedPrintReply, this,
-                 printer_query, reply_msg));
+  GetPrintSettingsForRenderViewParams settings_params;
+  settings_params.ask_user_for_settings = printing::PrinterQuery::ASK_USER;
+  settings_params.expected_page_count = params.expected_pages_count;
+  settings_params.has_selection = params.has_selection;
+  settings_params.margin_type = params.margin_type;
+
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&PrintingMessageFilter::GetPrintSettingsForRenderView, this,
+                 reply_msg->routing_id(), settings_params,
+                 base::Bind(&PrintingMessageFilter::OnScriptedPrintReply, this,
+                            printer_query, reply_msg),
+                 printer_query));
 }
 
 void PrintingMessageFilter::OnScriptedPrintReply(