Register clipboard image blob in the browser process to copy data less.

third_party/WebKit/Source/core/clipboard/DataObjectItem.cpp

Index: third_party/WebKit/Source/core/clipboard/DataObjectItem.cpp
diff --git a/third_party/WebKit/Source/core/clipboard/DataObjectItem.cpp b/third_party/WebKit/Source/core/clipboard/DataObjectItem.cpp
index 84fcd5638fec0a1e3727bca7d4b7b5280ae2b1b3..f7f309810c3aaf1a3ef65ae88402b444975e8ab3 100644
--- a/third_party/WebKit/Source/core/clipboard/DataObjectItem.cpp
+++ b/third_party/WebKit/Source/core/clipboard/DataObjectItem.cpp
@@ -116,20 +116,10 @@ Blob* DataObjectItem::getAsFile() const
 
     ASSERT(m_source == PasteboardSource);
     if (type() == mimeTypeImagePng) {
-        // FIXME: This is pretty inefficient. We copy the data from the browser
-        // to the renderer. We then place it in a blob in WebKit, which
-        // registers it and copies it *back* to the browser. When a consumer
-        // wants to read the data, we then copy the data back into the renderer.
-        // https://bugs.webkit.org/show_bug.cgi?id=58107 has been filed to track
-        // improvements to this code (in particular, add a registerClipboardBlob
-        // method to the blob registry; that way the data is only copied over
-        // into the renderer when it's actually read, not when the blob is
-        // initially constructed).
-        RefPtr<SharedBuffer> data = static_cast<PassRefPtr<SharedBuffer>>(Platform::current()->clipboard()->readImage(WebClipboard::BufferStandard));
-        OwnPtr<BlobData> blobData = BlobData::create();
-        blobData->appendBytes(data->data(), data->size());
-        blobData->setContentType(mimeTypeImagePng);
-        return Blob::create(BlobDataHandle::create(blobData.release(), data->size()));
+        WebBlobInfo blobInfo = Platform::current()->clipboard()->readImage(WebClipboard::BufferStandard);
+        if (blobInfo.size() < 0)
+            return nullptr;
+        return Blob::create(BlobDataHandle::create(blobInfo.uuid(), blobInfo.type(), blobInfo.size()));

[dmurph, 2016/04/12 00:10:23]

Hmmm.. Well if you went the register-blob-in-dispatcher-host-before-sending-it
approach, you would just call 
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

right after creating the blob here. Doing it this (hacky) way would require
documentation on the browser saying "please decrement the refcount once from the
renderer once you create the handle there".

maybe that's not the best way though haha

     }
 
     return nullptr;