Add AshDesktopMediaList and enable Desktop Capture API on Chrome OS.

ui/snapshot/snapshot_aura.cc

Index: ui/snapshot/snapshot_aura.cc
diff --git a/ui/snapshot/snapshot_aura.cc b/ui/snapshot/snapshot_aura.cc
index 1cebfe9be08f2c96ec257cba834d83209ed9b2a9..3df2e66923e2c47527d8cf5830f1acbd1d02d1a6 100644
--- a/ui/snapshot/snapshot_aura.cc
+++ b/ui/snapshot/snapshot_aura.cc
@@ -4,8 +4,13 @@
 
 #include "ui/snapshot/snapshot.h"
 
+#include "base/bind.h"
 #include "base/logging.h"
 #include "base/safe_numerics.h"
+#include "base/task_runner_util.h"
+#include "cc/output/copy_output_request.h"
+#include "cc/output/copy_output_result.h"
+#include "skia/ext/image_operations.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkPixelRef.h"
 #include "ui/aura/root_window.h"
@@ -15,6 +20,8 @@
 #include "ui/compositor/layer.h"
 #include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/display.h"
+#include "ui/gfx/image/image.h"
+#include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/rect_conversions.h"
 #include "ui/gfx/rect_f.h"
@@ -87,4 +94,55 @@ bool GrabWindowSnapshot(gfx::NativeWindow window,
       png_representation);
 }
 
+void OnFrameScalingFinished(
+    const GrapWindowSnapshotAsyncCallback& callback,
+    const SkBitmap& scaled_bitmap) {
+  callback.Run(gfx::Image(gfx::ImageSkia::CreateFrom1xBitmap(scaled_bitmap)));
+}
+
+void ScaleCopyOutputResult(
+    const GrapWindowSnapshotAsyncCallback& callback,
+    const gfx::Size& target_size,
+    scoped_refptr<base::TaskRunner> background_task_runner,
+    scoped_ptr<cc::CopyOutputResult> result) {
+  if (result->IsEmpty()) {
+    callback.Run(gfx::Image());
+    return;
+  }
+
+  // There are two overrides for skia::ImageOperations::Resize(), so we need get
+  // pointer to the right override explicitly (otherwise the base::Bind() call
+  // below won't compile).
+  SkBitmap (*resize_function)(const SkBitmap&,
+                              skia::ImageOperations::ResizeMethod, int, int,
+                              SkBitmap::Allocator* allocator) =
+      &skia::ImageOperations::Resize;
+
+  // TODO(sergeyu): Potentially images can be scaled on GPU before reading it
+  // from GPU. Image scaling is implemented in content::GlHelper, but it's can't
+  // be used here because it's not in content/public. Move the scaling code
+  // somewhere so that it can be reused here.
+  base::PostTaskAndReplyWithResult(
+      background_task_runner, FROM_HERE,
+      base::Bind(resize_function, *result->TakeBitmap(),
+                 skia::ImageOperations::RESIZE_GOOD,
+                 target_size.width(), target_size.height(),
+                 static_cast<SkBitmap::Allocator*>(NULL)),
+      base::Bind(&OnFrameScalingFinished, callback));
+}
+
+SNAPSHOT_EXPORT void GrapWindowSnapshotAsync(
+    gfx::NativeWindow window,
+    const gfx::Rect& source_rect,
+    const gfx::Size& target_size,
+    scoped_refptr<base::TaskRunner> background_task_runner,
+    const GrapWindowSnapshotAsyncCallback& callback) {
+  scoped_ptr<cc::CopyOutputRequest> request =
+      cc::CopyOutputRequest::CreateBitmapRequest(
+          base::Bind(&ScaleCopyOutputResult, callback, target_size,
+                     background_task_runner));
+  request->set_area(ui::ConvertRectToPixel(window->layer(), source_rect));
+  window->layer()->RequestCopyOfOutput(request.Pass());
+}
+
 }  // namespace ui