Only generate suggested filenames when actually dragging an image.

content/browser/web_contents/web_drag_source_mac.mm

 // 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.
 
 #import "content/browser/web_contents/web_drag_source_mac.h"
 
 #include <sys/param.h>
 
 #include <utility>
 
@@ skipping 34 matching lines @@
 using content::DropData;
 using content::PromiseFileFinalizer;
 using content::RenderViewHostImpl;
 
 namespace {
 
 // An unofficial standard pasteboard title type to be provided alongside the
 // |NSURLPboardType|.
 NSString* const kNSURLTitlePboardType = @"public.url-name";
 
-// Converts a base::string16 into a FilePath. Use this method instead of
-// -[NSString fileSystemRepresentation] to prevent exceptions from being thrown.
-// See http://crbug.com/78782 for more info.
-base::FilePath FilePathFromFilename(const base::string16& filename) {
-  NSString* str = SysUTF16ToNSString(filename);
-  char buf[MAXPATHLEN];
-  if (![str getFileSystemRepresentation:buf maxLength:sizeof(buf)])
-    return base::FilePath();
-  return base::FilePath(buf);
-}
-
-// Returns a filename appropriate for the drop data
-// TODO(viettrungluu): Refactor to make it common across platforms,
-// and move it somewhere sensible.
-base::FilePath GetFileNameFromDragData(const DropData& drop_data) {
-  base::FilePath file_name(
-      FilePathFromFilename(drop_data.file_description_filename));
-
-  // Images without ALT text will only have a file extension so we need to
-  // synthesize one from the provided extension and URL.
-  if (file_name.empty()) {
-    // Retrieve the name from the URL.
-    base::string16 suggested_filename =
-        net::GetSuggestedFilename(drop_data.url, "", "", "", "", "");
-    const std::string extension = file_name.Extension();
-    file_name = FilePathFromFilename(suggested_filename);
-    file_name = file_name.ReplaceExtension(extension);
-  }
-
-  return file_name;
-}
-
 // This helper's sole task is to write out data for a promised file; the caller
 // is responsible for opening the file. It takes the drop data and an open file
 // stream.
 void PromiseWriterHelper(const DropData& drop_data,
                          base::File file) {
   DCHECK(file.IsValid());
   file.WriteAtCurrentPos(drop_data.file_contents.data(),
                          drop_data.file_contents.length());
 }
 
@@ skipping 267 matching lines @@
                     owner:contentsView_];
   }
 
   // MIME type.
   std::string mimeType;
 
   // File.
   if (!dropData_->file_contents.empty() ||
       !dropData_->download_metadata.empty()) {
     if (dropData_->download_metadata.empty()) {
-      downloadFileName_ = GetFileNameFromDragData(*dropData_);
-      net::GetMimeTypeFromExtension(downloadFileName_.Extension(), &mimeType);
+      base::Optional<base::FilePath> suggestedFilename =
+          dropData_->GetSafeFilenameForImageFileContents();
+      if (suggestedFilename) {
+        downloadFileName_ = std::move(*suggestedFilename);
+        net::GetMimeTypeFromExtension(downloadFileName_.Extension(), &mimeType);
+      }
     } else {
       base::string16 mimeType16;
       base::FilePath fileName;
       if (content::ParseDownloadMetadata(
               dropData_->download_metadata,
               &mimeType16,
               &fileName,
               &downloadURL_)) {
         // Generate the file name based on both mime type and proposed file
         // name.
@@ skipping 82 matching lines @@
 - (NSImage*)dragImage {
   if (dragImage_)
     return dragImage_;
 
   // Default to returning a generic image.
   return content::GetContentClient()->GetNativeImageNamed(
       IDR_DEFAULT_FAVICON).ToNSImage();
 }
 
 @end  // @implementation WebDragSource (Private)