Add SetImageData api to chrome.clipboard.

chrome/browser/extensions/clipboard_extension_helper.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.h"
+
+#include "base/macros.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/synchronization/cancellation_flag.h"
+#include "chrome/browser/image_decoder.h"
+#include "extensions/browser/api/clipboard/clipboard_api.h"
+#include "ui/base/clipboard/scoped_clipboard_writer.h"
+
+using content::BrowserThread;
+
+namespace extensions {
+
+class ClipboardExtensionHelper::ClipboardImageDataDecoder
+    : public ImageDecoder::ImageRequest {
+ public:
+  explicit ClipboardImageDataDecoder(ClipboardExtensionHelper* owner)
+      : owner_(owner) {}
+
+  void Start(const std::vector<char>& image_data, const std::string& type) {
+    DCHECK_CURRENTLY_ON(BrowserThread::UI);
+    std::string image_data_str(image_data.begin(), image_data.end());
+
+    ImageDecoder::ImageCodec codec = ImageDecoder::DEFAULT_CODEC;
+    std::string encoding_type = base::ToLowerASCII(type);
+#if defined(OS_CHROMEOS)
+    if (encoding_type == "png") {
+      codec = ImageDecoder::ROBUST_PNG_CODEC;
+    } else if (encoding_type == "jpeg") {
+      codec = ImageDecoder::ROBUST_JPEG_CODEC;
+    } else {
+      OnDecodeImageFailed();
+      return;
+    }
+#endif
+
+    ImageDecoder::StartWithOptions(this, image_data_str, codec, true);

[dcheng, 2016/10/04 05:13:27]

IIRC, ImageDecoder internally uses std::vector<uint8_t>. Is there a way for
extensions bindings to give us that type, so we can avoid copying the data from
std::vector<char> -> std::string -> std::vector<uint8_t>?

[jennyz, 2016/10/04 23:53:54]

The automatically generated clipboard.h maps the ArrayBuffer data type from
extension API to std::vector<char>. I may not have the freedom to change the
extensions bindings to give use std::vector<uint8_t> type. 

namespace SetImageData {

struct Params {
  static std::unique_ptr<Params> Create(const base::ListValue& args);
  ~Params();

  // The encoded image data.
  std::vector<char> image_data;
...
}
...

+  }
+
+  void Cancel() {
+    cancel_flag_.Set();
+    owner_->OnImageDecodeCancel();
+  }
+
+  void OnImageDecoded(const SkBitmap& decoded_image) override {
+    if (!cancel_flag_.IsSet())
+      owner_->OnImageDecoded(decoded_image);
+    delete this;
+  }
+
+  void OnDecodeImageFailed() override {
+    if (!cancel_flag_.IsSet())
+      owner_->OnImageDecodeFailure();
+    delete this;
+  }
+
+ private:
+  ClipboardExtensionHelper* owner_;
+  base::CancellationFlag cancel_flag_;
+
+  DISALLOW_COPY_AND_ASSIGN(ClipboardImageDataDecoder);
+};
+
+ClipboardExtensionHelper::ClipboardImageDataDecoder*
+    ClipboardExtensionHelper::clipboard_image_data_decoder_;
+
+ClipboardExtensionHelper::ClipboardExtensionHelper()
+    : image_save_success_callback_(nullptr),
+      image_save_error_callback_(nullptr),
+      clipboard_writer_(
+          new ui::ScopedClipboardWriter(ui::CLIPBOARD_TYPE_COPY_PASTE)) {}
+
+ClipboardExtensionHelper::~ClipboardExtensionHelper() {}
+
+void ClipboardExtensionHelper::DecodeAndSaveImageData(
+    const std::vector<char>& data,
+    const std::string& type,
+    const base::Closure& success_callback,
+    const base::Closure& 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_)
+    clipboard_image_data_decoder_->Cancel();
+
+  clipboard_image_data_decoder_ = new ClipboardImageDataDecoder(this);
+  image_save_success_callback_ = success_callback;
+  image_save_error_callback_ = error_callback;
+  clipboard_image_data_decoder_->Start(data, type);
+}
+
+void ClipboardExtensionHelper::OnImageDecodeFailure() {
+  clipboard_image_data_decoder_ = NULL;
+  image_save_error_callback_.Run();
+}
+
+void ClipboardExtensionHelper::OnImageDecoded(const SkBitmap& bitmap) {
+  clipboard_image_data_decoder_ = NULL;
+
+  // Write the decoded image data to clipboard.
+  if (!bitmap.empty() && !bitmap.isNull())
+    clipboard_writer_->WriteImage(bitmap);
+  clipboard_writer_.reset(
+      new ui::ScopedClipboardWriter(ui::CLIPBOARD_TYPE_COPY_PASTE));
+
+  image_save_success_callback_.Run();
+}
+
+void ClipboardExtensionHelper::OnImageDecodeCancel() {
+  image_save_error_callback_.Run();
+}
+
+}  // namespace extensions