Moved thumbnail generation code from chrome/browser/android to chrome/browser

This will be required for supplying thumbnails to download OfflineContentProvider.
Since the invoking code lives in chrome/browser, we are moving the thumbnail
generation part to platform-independent code as well

Bug: 855330
Change-Id: Ic397e50faa511c83f1241d4c961c5e888ea8d272
Reviewed-on: https://chromium-review.googlesource.com/1111652Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Shakti Sahu <shaktisahu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570252}

chrome/browser/BUILD.gn

@@ -436,6 +436,8 @@ jumbo_split_static_library("browser") {
     "download/download_ui_controller.cc",
     "download/download_ui_controller.h",
     "download/drag_download_item.h",
+    "download/image_thumbnail_request.cc",
+    "download/image_thumbnail_request.h",
     "download/save_package_file_picker.cc",
     "download/save_package_file_picker.h",
     "download/trusted_sources_manager.cc",

chrome/browser/android/widget/thumbnail_generator.cc

@@ -7,137 +7,15 @@
 #include <memory>
 
 #include "base/android/jni_string.h"
-#include "base/files/file_path.h"
-#include "base/files/file_util.h"
-#include "base/memory/weak_ptr.h"
-#include "base/task_scheduler/post_task.h"
 #include "base/threading/thread_restrictions.h"
 #include "content/public/browser/browser_thread.h"
 #include "jni/ThumbnailGenerator_jni.h"
-#include "skia/ext/image_operations.h"
-#include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/android/java_bitmap.h"
-#include "ui/gfx/skbitmap_operations.h"
 
 class SkBitmap;
 
 using base::android::JavaParamRef;
 
-namespace {
-
-// Ignore image files that are too large to avoid long delays.
-const int64_t kMaxImageSize = 10 * 1024 * 1024;  // 10 MB
-
-std::string LoadImageData(const base::FilePath& path) {
-  base::AssertBlockingAllowed();
-
-  // Confirm that the file's size is within our threshold.
-  int64_t file_size;
-  if (!base::GetFileSize(path, &file_size) || file_size > kMaxImageSize) {
-    LOG(ERROR) << "Unexpected file size: " << path.MaybeAsASCII() << ", "
-               << file_size;
-    return std::string();
-  }
-
-  std::string data;
-  bool success = base::ReadFileToString(path, &data);
-
-  // Make sure the file isn't empty.
-  if (!success || data.empty()) {
-    LOG(ERROR) << "Failed to read file: " << path.MaybeAsASCII();
-    return std::string();
-  }
-
-  return data;
-}
-
-SkBitmap ScaleDownBitmap(int icon_size, const SkBitmap& decoded_image) {
-  DCHECK(!content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-
-  if (decoded_image.drawsNothing())
-    return decoded_image;
-
-  // Shrink the image down so that its smallest dimension is equal to or
-  // smaller than the requested size.
-  int min_dimension = std::min(decoded_image.width(), decoded_image.height());
-
-  if (min_dimension <= icon_size)
-    return decoded_image;
-
-  uint64_t width = static_cast<uint64_t>(decoded_image.width());
-  uint64_t height = static_cast<uint64_t>(decoded_image.height());
-  return skia::ImageOperations::Resize(
-      decoded_image, skia::ImageOperations::RESIZE_BEST,
-      width * icon_size / min_dimension, height * icon_size / min_dimension);
-}
-
-class ImageThumbnailRequest : public ImageDecoder::ImageRequest {
- public:
-  ImageThumbnailRequest(int icon_size,
-                        base::OnceCallback<void(const SkBitmap&)> callback)
-      : icon_size_(icon_size),
-        callback_(std::move(callback)),
-        weak_ptr_factory_(this) {
-    DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  }
-
-  ~ImageThumbnailRequest() override {
-    DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  }
-
-  void Start(const base::FilePath& path) {
-    DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-    base::PostTaskWithTraitsAndReplyWithResult(
-        FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_BLOCKING},
-        base::BindOnce(&LoadImageData, path),
-        base::BindOnce(&ImageThumbnailRequest::OnLoadComplete,
-                       weak_ptr_factory_.GetWeakPtr()));
-  }
-
- private:
-  // ImageDecoder::ImageRequest implementation.
-  void OnImageDecoded(const SkBitmap& decoded_image) override {
-    DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-    base::PostTaskWithTraitsAndReplyWithResult(
-        FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_BLOCKING},
-        base::BindOnce(&ScaleDownBitmap, icon_size_, decoded_image),
-        base::BindOnce(&ImageThumbnailRequest::FinishRequest,
-                       weak_ptr_factory_.GetWeakPtr()));
-  }
-
-  void OnDecodeImageFailed() override {
-    DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-    LOG(ERROR) << "Failed to decode image.";
-    FinishRequest(SkBitmap());
-  }
-
-  void OnLoadComplete(const std::string& data) {
-    DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-    if (data.empty()) {
-      FinishRequest(SkBitmap());
-      return;
-    }
-
-    ImageDecoder::Start(this, data);
-  }
-
-  void FinishRequest(const SkBitmap& thumbnail) {
-    DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-    content::BrowserThread::PostTask(
-        content::BrowserThread::UI, FROM_HERE,
-        base::BindOnce(std::move(callback_), thumbnail));
-    delete this;
-  }
-
-  const int icon_size_;
-  base::OnceCallback<void(const SkBitmap&)> callback_;
-  base::WeakPtrFactory<ImageThumbnailRequest> weak_ptr_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(ImageThumbnailRequest);
-};
-
-}  // namespace
-
 ThumbnailGenerator::ThumbnailGenerator(const JavaParamRef<jobject>& jobj)
     : java_delegate_(jobj), weak_factory_(this) {
   DCHECK(!jobj.is_null());

chrome/browser/android/widget/thumbnail_generator.h

@@ -9,7 +9,7 @@
 
 #include "base/android/jni_android.h"
 #include "base/memory/weak_ptr.h"
-#include "chrome/browser/image_decoder.h"
+#include "chrome/browser/download/image_thumbnail_request.h"
 
 // Kicks off asynchronous pipelines for creating thumbnails for local files.
 // The native-side ThumbnailGenerator is owned by the Java-side and can be

chrome/browser/download/image_thumbnail_request.cc

+// Copyright 2018 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/download/image_thumbnail_request.h"
+
+#include <memory>
+
+#include "base/files/file_util.h"
+#include "base/task_scheduler/post_task.h"
+#include "base/threading/thread_restrictions.h"
+#include "content/public/browser/browser_thread.h"
+#include "skia/ext/image_operations.h"
+
+namespace {
+
+// Ignore image files that are too large to avoid long delays.
+const int64_t kMaxImageSize = 10 * 1024 * 1024;  // 10 MB
+
+std::string LoadImageData(const base::FilePath& path) {
+  base::AssertBlockingAllowed();
+
+  // Confirm that the file's size is within our threshold.
+  int64_t file_size;
+  if (!base::GetFileSize(path, &file_size) || file_size > kMaxImageSize) {
+    LOG(ERROR) << "Unexpected file size: " << path.MaybeAsASCII() << ", "
+               << file_size;
+    return std::string();
+  }
+
+  std::string data;
+  bool success = base::ReadFileToString(path, &data);
+
+  // Make sure the file isn't empty.
+  if (!success || data.empty()) {
+    LOG(ERROR) << "Failed to read file: " << path.MaybeAsASCII();
+    return std::string();
+  }
+
+  return data;
+}
+
+SkBitmap ScaleDownBitmap(int icon_size, const SkBitmap& decoded_image) {
+  DCHECK(!content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+
+  if (decoded_image.drawsNothing())
+    return decoded_image;
+
+  // Shrink the image down so that its smallest dimension is equal to or
+  // smaller than the requested size.
+  int min_dimension = std::min(decoded_image.width(), decoded_image.height());
+
+  if (min_dimension <= icon_size)
+    return decoded_image;
+
+  uint64_t width = static_cast<uint64_t>(decoded_image.width());
+  uint64_t height = static_cast<uint64_t>(decoded_image.height());
+  return skia::ImageOperations::Resize(
+      decoded_image, skia::ImageOperations::RESIZE_BEST,
+      width * icon_size / min_dimension, height * icon_size / min_dimension);
+}
+
+}  // namespace
+
+ImageThumbnailRequest::ImageThumbnailRequest(
+    int icon_size,
+    base::OnceCallback<void(const SkBitmap&)> callback)
+    : icon_size_(icon_size),
+      callback_(std::move(callback)),
+      weak_ptr_factory_(this) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+}
+
+ImageThumbnailRequest::~ImageThumbnailRequest() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+}
+
+void ImageThumbnailRequest::Start(const base::FilePath& path) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  base::PostTaskWithTraitsAndReplyWithResult(
+      FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_BLOCKING},
+      base::BindOnce(&LoadImageData, path),
+      base::BindOnce(&ImageThumbnailRequest::OnLoadComplete,
+                     weak_ptr_factory_.GetWeakPtr()));
+}
+
+void ImageThumbnailRequest::OnImageDecoded(const SkBitmap& decoded_image) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  base::PostTaskWithTraitsAndReplyWithResult(
+      FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_BLOCKING},
+      base::BindOnce(&ScaleDownBitmap, icon_size_, decoded_image),
+      base::BindOnce(&ImageThumbnailRequest::FinishRequest,
+                     weak_ptr_factory_.GetWeakPtr()));
+}
+
+void ImageThumbnailRequest::OnDecodeImageFailed() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  LOG(ERROR) << "Failed to decode image.";
+  FinishRequest(SkBitmap());
+}
+
+void ImageThumbnailRequest::OnLoadComplete(const std::string& data) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  if (data.empty()) {
+    FinishRequest(SkBitmap());
+    return;
+  }
+
+  ImageDecoder::Start(this, data);
+}
+
+void ImageThumbnailRequest::FinishRequest(const SkBitmap& thumbnail) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::BindOnce(std::move(callback_), thumbnail));
+  delete this;
+}

chrome/browser/download/image_thumbnail_request.h

+// Copyright 2018 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.
+
+#ifndef CHROME_BROWSER_DOWNLOAD_IMAGE_THUMBNAIL_REQUEST_H_
+#define CHROME_BROWSER_DOWNLOAD_IMAGE_THUMBNAIL_REQUEST_H_
+
+#include <string>
+
+#include "base/files/file_path.h"
+#include "base/memory/weak_ptr.h"
+#include "chrome/browser/image_decoder.h"
+
+// Helper class to generate thumbnail for a given local image file with a given
+// max size. Must be invoked on the browser thread.
+class ImageThumbnailRequest : public ImageDecoder::ImageRequest {
+ public:
+  ImageThumbnailRequest(int icon_size,
+                        base::OnceCallback<void(const SkBitmap&)> callback);
+
+  ~ImageThumbnailRequest() override;
+
+  // Kicks off an asynchronous process to retrieve the thumbnail for the file
+  // located at |file_path| with a max size of |icon_size_| in each dimension.
+  // Invokes the |callback_| method when finished.
+  void Start(const base::FilePath& path);
+
+ private:
+  // ImageDecoder::ImageRequest implementation.
+  void OnImageDecoded(const SkBitmap& decoded_image) override;
+
+  void OnDecodeImageFailed() override;
+
+  void OnLoadComplete(const std::string& data);
+
+  void FinishRequest(const SkBitmap& thumbnail);
+
+  const int icon_size_;
+  base::OnceCallback<void(const SkBitmap&)> callback_;
+  base::WeakPtrFactory<ImageThumbnailRequest> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(ImageThumbnailRequest);
+};
+
+#endif  // CHROME_BROWSER_DOWNLOAD_IMAGE_THUMBNAIL_REQUEST_H_