Defer request to print a PDF when the user initiates the entire frame and the PDF hasn't loaded.

chrome/renderer/printing/print_web_view_helper.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/renderer/printing/print_web_view_helper.h"
 
 #include <string>
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
@@ skipping 773 matching lines @@
       is_scripted_print_throttling_disabled_(IsPrintThrottlingDisabled()),
       is_print_ready_metafile_sent_(false),
       ignore_css_margins_(false),
       user_cancelled_scripted_print_count_(0),
       is_scripted_printing_blocked_(false),
       notify_browser_of_print_failure_(true),
       print_for_preview_(false),
       print_node_in_progress_(false),
       is_loading_(false),
       is_scripted_preview_delayed_(false),
-      weak_ptr_factory_(this) {
+      weak_ptr_factory_(this),
+      on_stop_loading_type_(PRINT_PREVIEW_SCRIPTED) {
 }
 
 PrintWebViewHelper::~PrintWebViewHelper() {}
 
 bool PrintWebViewHelper::IsScriptInitiatedPrintAllowed(
     blink::WebFrame* frame, bool user_initiated) {
 #if defined(OS_ANDROID)
   return false;
 #endif  // defined(OS_ANDROID)
   if (is_scripted_printing_blocked_)
     return false;
   // If preview is enabled, then the print dialog is tab modal, and the user
   // can always close the tab on a mis-behaving page (the system print dialog
   // is app modal). If the print was initiated through user action, don't
   // throttle. Or, if the command line flag to skip throttling has been set.
   if (!is_scripted_print_throttling_disabled_ &&
       !is_preview_enabled_ &&
       !user_initiated)
     return !IsScriptInitiatedPrintTooFrequent(frame);
   return true;
 }
 
 void PrintWebViewHelper::DidStartLoading() {
   is_loading_ = true;
 }
 
 void PrintWebViewHelper::DidStopLoading() {
   is_loading_ = false;
-  ShowScriptedPrintPreview();
+
+  // |on_stop_loading_type_| should be reset to the default value
+  // PRINT_PREVIEW_SCRIPTED after is its equal to
+  // PRINT_PREVIEW_USER_INITIATED_ENTIRE_FRAME because the race condition has
+  // been handled.
+  if (on_stop_loading_type_ == PRINT_PREVIEW_SCRIPTED) {
+    ShowScriptedPrintPreview();
+  } else if (on_stop_loading_type_ ==
+             PRINT_PREVIEW_USER_INITIATED_ENTIRE_FRAME) {
+    RequestPrintPreview(on_stop_loading_type_);
+    on_stop_loading_type_ = PRINT_PREVIEW_SCRIPTED;
+  }
 }
 
 // Prints |frame| which called window.print().
 void PrintWebViewHelper::PrintPage(blink::WebLocalFrame* frame,
                                    bool user_initiated) {
   DCHECK(frame);
 
   // Allow Prerendering to cancel this print request if necessary.
   if (prerender::PrerenderHelper::IsPrerendering(
           render_view()->GetMainRenderFrame())) {
@@ skipping 883 matching lines @@
             base::Bind(&PrintWebViewHelper::ShowScriptedPrintPreview,
                        weak_ptr_factory_.GetWeakPtr()));
       }
       IPC::SyncMessage* msg =
           new PrintHostMsg_SetupScriptedPrintPreview(routing_id());
       msg->EnableMessagePumping();
       Send(msg);
       is_scripted_preview_delayed_ = false;
       return;
     }
     case PRINT_PREVIEW_USER_INITIATED_ENTIRE_FRAME: {

[ivandavid, 2014/08/13 20:58:55]

This is the only case where we should handle the race condition. Handling this
condition in PRINT_PREVIEW_USER_INITIATED_SELECTION will break sheets and
doesn't seem appropriate as the only problem was with
PRINT_PREVIEW_USER_INITIATED_ENTIRE_FRAME.

[Vitaly Buka (NO REVIEWS), 2014/08/13 23:39:45]

No, it is not.

Try to 
1. open huge pdf (for example pdf reference)
2. before it finish loading, click PRINT icon in bottom right corner
3. It would get into PRINT_PREVIEW_USER_INITIATED_CONTEXT_NODE and open empty
preview



On 2014/08/13 20:58:55, ivandavid wrote:

[ivandavid, 2014/08/14 03:38:13]

Done.

[ivandavid, 2014/08/14 03:38:13]

Oh OK. I figured why the PRINT_PREVIEW_USER_INITIATED_CONTEXT_NODE code path was
causing sheets to not work. See the comment in ppb_pdf_impl.cc

+      // Handles case where this function has been called, but DidStopLoading()
+      // hasn't been called yet. RequestPrintPreview() will be called again, at
+      // the end of DidStopLoading() with the same value for |type|.
+      if (is_loading_ && GetPlugin(print_preview_context_.source_frame())) {
+        on_stop_loading_type_ = PRINT_PREVIEW_USER_INITIATED_ENTIRE_FRAME;
+        return;
+      }
+
       break;
     }
     case PRINT_PREVIEW_USER_INITIATED_SELECTION: {
       DCHECK(has_selection);
       params.selection_only = has_selection;

[Vitaly Buka (NO REVIEWS), 2014/08/13 23:39:45]

could you please put DCHECK(!GetPlugin(print_preview_context_.source_frame()));
here

       break;
     }
     case PRINT_PREVIEW_USER_INITIATED_CONTEXT_NODE: {
       params.webnode_only = true;
       break;
     }
     default: {
       NOTREACHED();
       return;
     }
@@ skipping 288 matching lines @@
 }
 
 void PrintWebViewHelper::PrintPreviewContext::ClearContext() {
   prep_frame_view_.reset();
   metafile_.reset();
   pages_to_render_.clear();
   error_ = PREVIEW_ERROR_NONE;
 }
 
 }  // namespace printing