Print Preview: Detecting plugin existence before generating the preview.

chrome/browser/ui/webui/print_preview_ui_html_source.cc

 // Copyright (c) 2011 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/ui/webui/print_preview_ui_html_source.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/message_loop.h"
@@ skipping 142 matching lines @@
     char* preview_data = reinterpret_cast<char*>(data_.first->memory());
     uint32 preview_data_size = data_.second;
 
     scoped_refptr<RefCountedBytes> html_bytes(new RefCountedBytes);
     html_bytes->data.resize(preview_data_size);
     std::vector<unsigned char>::iterator it = html_bytes->data.begin();
     for (uint32 i = 0; i < preview_data_size; ++i, ++it)
       *it = *(preview_data + i);
     SendResponse(request_id, html_bytes);
     return;
+  } else if (path == "blank.pdf") {
+    const unsigned char blank_pdf[] = "%PDF-1.4\n3 0 obj<</Type/Catalog/Pages"

[vandebo (ex-Chrome), 2011/05/11 22:13:54]

kBlankPDF
All the start quotes should line up.

[dpapad, 2011/05/11 23:31:03]

It seems like there is no need to pass actual pdf data. Passing no data works
just as well.

+        " 1 0 R>>endobj 2 0 obj<</Type/Page/Parent 1 0 R/Resources"
+        "<<>>/MediaBox[0 0 612 792]>>endobj 1 0 obj<</Type"
+        "/Pages/Kids[2 0 R]/Count 1>>endobj\nxref\n0 4\n"
+        "0000000000 65535 f \n0000000129 00000 n \n"
+        "0000000052 00000 n \n0000000009 00000 n \ntrailer<<"
+        "/Size 4/Root 3 0 R>>startxref\n178\n%%EOF\n";
+    scoped_refptr<RefCountedStaticMemory> dummy_bytes(

[vandebo (ex-Chrome), 2011/05/11 22:13:54]

dummy_bytes -> blank_bytes.

[dpapad, 2011/05/11 23:31:03]

Done.

+        new RefCountedStaticMemory(blank_pdf, sizeof(blank_pdf)));
+    SendResponse(request_id, dummy_bytes);
+    return;
   } else {
     // Invalid request.
     scoped_refptr<RefCountedBytes> empty_bytes(new RefCountedBytes);
     SendResponse(request_id, empty_bytes);
     return;
   }
 }
 
 std::string PrintPreviewUIHTMLSource::GetMimeType(
     const std::string& path) const {
   // Print Preview Index page.
   if (path.empty())
     return "text/html";
   // Print Preview data.
   return "application/pdf";
 }