update functionalities to snapshot.cc.

1. Accelerate GrabWindowSnapshotAsyncPNG by
   using gfx::PNGCodec::FastEncodeBGRASkBitmap,
   which halves down the encoding time
2. Add GrabWindowSnapshotAsyncJPEG for scenarios
   that require low latency since JPEG encoder
   typically is 5x faster than PNG encoder.

BUG=b/37167971
TEST=local benchmark GrabWindowSnapshotAsyncPNG
  indicates 2x speedup; GrabWindowSnapshotAsyncJPEG
  works.

Review-Url: https://codereview.chromium.org/2815913007
Cr-Commit-Position: refs/heads/master@{#465132}

ui/snapshot/snapshot.cc

@@ -7,22 +7,40 @@
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/task_runner_util.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/image/image.h"
+#include "ui/gfx/image/image_skia.h"
+#include "ui/gfx/image/image_util.h"
 
 namespace ui {
 
 namespace {
 
-scoped_refptr<base::RefCountedMemory> EncodeImage(const gfx::Image& image) {
-  return image.As1xPNGBytes();
+scoped_refptr<base::RefCountedMemory> EncodeImageAsPNG(
+    const gfx::Image& image) {
+  std::vector<uint8_t> result;
+  DCHECK(!image.AsImageSkia().GetRepresentation(1.0f).is_null());
+  gfx::PNGCodec::FastEncodeBGRASkBitmap(image.AsBitmap(), true, &result);
+  return new base::RefCountedBytes(result);
+}
+
+scoped_refptr<base::RefCountedMemory> EncodeImageAsJPEG(
+    const gfx::Image& image) {
+  std::vector<uint8_t> result;
+  DCHECK(!image.AsImageSkia().GetRepresentation(1.0f).is_null());
+  gfx::JPEG1xEncodedDataFromImage(image, 100, &result);
+  return new base::RefCountedBytes(result);
 }
 
-void EncodeImageAndSchedulePNGCallback(
+void EncodeImageAndScheduleCallback(
+    scoped_refptr<base::RefCountedMemory> (*encode_func)(const gfx::Image&),
     scoped_refptr<base::TaskRunner> background_task_runner,
-    const GrabWindowSnapshotAsyncPNGCallback& callback,
+    const base::Callback<void(scoped_refptr<base::RefCountedMemory> data)>&
+        callback,
     const gfx::Image& image) {
   base::PostTaskAndReplyWithResult(background_task_runner.get(), FROM_HERE,
-                                   base::Bind(EncodeImage, image), callback);
+                                   base::Bind(encode_func, image), callback);
 }
 
 }  // namespace
@@ -34,7 +52,18 @@ void GrabWindowSnapshotAsyncPNG(
     const GrabWindowSnapshotAsyncPNGCallback& callback) {
   GrabWindowSnapshotAsync(
       window, source_rect,
-      base::Bind(EncodeImageAndSchedulePNGCallback,
+      base::Bind(EncodeImageAndScheduleCallback, &EncodeImageAsPNG,
+                 std::move(background_task_runner), callback));
+}
+
+void GrabWindowSnapshotAsyncJPEG(
+    gfx::NativeWindow window,
+    const gfx::Rect& source_rect,
+    scoped_refptr<base::TaskRunner> background_task_runner,
+    const GrabWindowSnapshotAsyncJPEGCallback& callback) {
+  GrabWindowSnapshotAsync(
+      window, source_rect,
+      base::Bind(EncodeImageAndScheduleCallback, &EncodeImageAsJPEG,
                  std::move(background_task_runner), callback));
 }
 

ui/snapshot/snapshot.h

@@ -61,14 +61,22 @@ SNAPSHOT_EXPORT void GrabViewSnapshotAsync(
     const gfx::Rect& source_rect,
     const GrabWindowSnapshotAsyncCallback& callback);
 
-typedef base::Callback<void(scoped_refptr<base::RefCountedMemory> png_data)>
-    GrabWindowSnapshotAsyncPNGCallback;
+using GrabWindowSnapshotAsyncPNGCallback =
+    base::Callback<void(scoped_refptr<base::RefCountedMemory> data)>;
 SNAPSHOT_EXPORT void GrabWindowSnapshotAsyncPNG(
     gfx::NativeWindow window,
     const gfx::Rect& source_rect,
     scoped_refptr<base::TaskRunner> background_task_runner,
     const GrabWindowSnapshotAsyncPNGCallback& callback);
 
+using GrabWindowSnapshotAsyncJPEGCallback =
+    base::Callback<void(scoped_refptr<base::RefCountedMemory> data)>;
+SNAPSHOT_EXPORT void GrabWindowSnapshotAsyncJPEG(
+    gfx::NativeWindow window,
+    const gfx::Rect& source_rect,
+    scoped_refptr<base::TaskRunner> background_task_runner,
+    const GrabWindowSnapshotAsyncJPEGCallback& callback);
+
 }  // namespace ui
 
 #endif  // UI_SNAPSHOT_SNAPSHOT_H_