Add SetImageData api to chrome.clipboard.

chrome/browser/extensions/clipboard_extension_helper_chromeos.cc

+// Copyright 2016 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/extensions/clipboard_extension_helper_chromeos.h"
+
+#include "base/callback_helpers.h"
+#include "base/macros.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/synchronization/cancellation_flag.h"
+#include "chrome/browser/image_decoder.h"
+#include "ui/base/clipboard/scoped_clipboard_writer.h"
+
+using content::BrowserThread;
+
+namespace extensions {
+
+namespace clipboard = api::clipboard;
+
+class ClipboardExtensionHelper::ClipboardImageDataDecoder
+    : public ImageDecoder::ImageRequest {
+ public:
+  explicit ClipboardImageDataDecoder(ClipboardExtensionHelper* owner)
+      : owner_(owner) {}
+
+  ~ClipboardImageDataDecoder() override { ImageDecoder::Cancel(this); }
+
+  bool has_request_pending() const { return has_request_pending_; }
+
+  void Start(const std::vector<char>& image_data, clipboard::ImageType type) {
+    DCHECK_CURRENTLY_ON(BrowserThread::UI);
+    std::string image_data_str(image_data.begin(), image_data.end());
+
+    ImageDecoder::ImageCodec codec = ImageDecoder::DEFAULT_CODEC;
+    switch (type) {
+      case clipboard::IMAGE_TYPE_PNG:
+        codec = ImageDecoder::ROBUST_PNG_CODEC;
+        break;
+      case clipboard::IMAGE_TYPE_JPEG:
+        codec = ImageDecoder::ROBUST_JPEG_CODEC;
+        break;
+      default:
+        OnDecodeImageFailed();
+        break;
+    }
+
+    has_request_pending_ = true;
+    ImageDecoder::StartWithOptions(this, image_data_str, codec, true);
+  }
+
+  void Cancel() {
+    has_request_pending_ = false;
+    ImageDecoder::Cancel(this);
+    owner_->OnImageDecodeCancel();
+  }
+
+  void OnImageDecoded(const SkBitmap& decoded_image) override {
+    has_request_pending_ = false;
+    owner_->OnImageDecoded(decoded_image);
+  }
+
+  void OnDecodeImageFailed() override {
+    has_request_pending_ = false;
+    owner_->OnImageDecodeFailure();
+  }
+
+ private:
+  ClipboardExtensionHelper* owner_;  // Not owned.
+  bool has_request_pending_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(ClipboardImageDataDecoder);
+};
+
+ClipboardExtensionHelper::ClipboardExtensionHelper() {
+  clipboard_image_data_decoder_.reset(new ClipboardImageDataDecoder(this));
+}
+
+ClipboardExtensionHelper::~ClipboardExtensionHelper() {}
+
+void ClipboardExtensionHelper::DecodeAndSaveImageData(
+    const std::vector<char>& data,
+    clipboard::ImageType type,
+    const base::Closure& success_callback,
+    const base::Callback<void(const std::string&)>& error_callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+
+  // If there is a previous image decoding request still running, cancel it
+  // first. We only need the most recent image save request be completed.
+  if (clipboard_image_data_decoder_->has_request_pending())
+    clipboard_image_data_decoder_->Cancel();

[Devlin, 2016/12/21 23:58:38]

Have you thought about the case of multiple extensions trying to use this at the
same time?  Doesn't this mean that only that last extension call gets the
result?

[jennyz, 2016/12/22 22:45:21]

In the case of multiple extensions trying to this at the "same" time to save
image onto the clipboard, since the clipboard can only store one image data,
like "paste" case, we still only need the same request win, it sets image data
on the clipboard. I have updated the comment to make this clear.

[Devlin, 2016/12/27 17:08:00]

Should we send a different error, then?  Rather than just saying "Image data
decoding failed"?

[jennyz, 2016/12/29 05:16:03]

We are sending a different error: "Request canceled", see
ClipboardExtensionHelper::OnImageDecodeCancel().

+
+  image_save_success_callback_ = success_callback;
+  image_save_error_callback_ = error_callback;
+  clipboard_image_data_decoder_->Start(data, type);
+}
+
+void ClipboardExtensionHelper::OnImageDecodeFailure() {
+  base::ResetAndReturn(&image_save_error_callback_)
+      .Run("Image data decoding failed");
+}
+
+void ClipboardExtensionHelper::OnImageDecoded(const SkBitmap& bitmap) {
+  {
+    ui::ScopedClipboardWriter scw(ui::CLIPBOARD_TYPE_COPY_PASTE);
+    // Write the decoded image data to clipboard.
+    if (!bitmap.empty() && !bitmap.isNull())
+      scw.WriteImage(bitmap);
+  }
+  base::ResetAndReturn(&image_save_success_callback_).Run();
+}
+
+void ClipboardExtensionHelper::OnImageDecodeCancel() {
+  base::ResetAndReturn(&image_save_error_callback_).Run("Request canceled");
+}
+
+}  // namespace extensions