Revert of Refactor download image-MIME-type-detection code.

chrome/browser/download/download_commands.cc

Index: chrome/browser/download/download_commands.cc
diff --git a/chrome/browser/download/download_commands.cc b/chrome/browser/download/download_commands.cc
index eb2ca17f41fc95f65bae1c66bb1afb81a30e522c..0f2417e1a7b7e17e8d1468b54b442cfba6853114 100644
--- a/chrome/browser/download/download_commands.cc
+++ b/chrome/browser/download/download_commands.cc
@@ -27,6 +27,7 @@
 #include "chrome/common/url_constants.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/google/core/browser/google_util.h"
+#include "components/mime_util/mime_util.h"
 #include "grit/theme_resources.h"
 #include "net/base/url_util.h"
 #include "ui/base/clipboard/scoped_clipboard_writer.h"
@@ -382,11 +383,23 @@
 void DownloadCommands::CopyFileAsImageToClipboard() const {
   if (download_item_->GetState() != content::DownloadItem::COMPLETE ||
       download_item_->GetReceivedBytes() > kMaxImageClipboardSize) {
-    return;
-  }
-
-  if (!DownloadItemModel(download_item_).HasSupportedImageMimeType())
-    return;
+      return;
+  }
+
+  // TODO(yoshiki): Refine the code by combining the common logic with the
+  // preview in DownloadItemNotification.
+  std::string mime = download_item_->GetMimeType();
+  if (!mime_util::IsSupportedImageMimeType(mime)) {
+    base::FilePath::StringType extension_with_dot =
+        download_item_->GetTargetFilePath().FinalExtension();
+    if (extension_with_dot.empty() ||
+        !net::GetWellKnownMimeTypeFromExtension(extension_with_dot.substr(1),
+                                                &mime) ||
+        !mime_util::IsSupportedImageMimeType(mime)) {
+      // It seems a non-image file.
+      return;
+    }
+  }
 
   base::FilePath file_path = download_item_->GetFullPath();
   ImageClipboardCopyManager::Start(file_path);