Revert of Delete the class WebRtcVideoCapturerAdapter::MediaVideoFrameFactory...

Revert of Delete the class WebRtcVideoCapturerAdapter::MediaVideoFrameFactory (patchset #5 id:80001 of https://codereview.chromium.org/2244213002/ )

Reason for revert:
Somehow breaks timestamping. Reverting for investigation. To reproduce, run

./browser_tests --gtest_filter='WebRtcVideoQualityBrowserTests/WebRtcVideoQualityBrowserTest*' --run-manual --ui-test-action-max-timeout=200000

This produces lots of warnings like

[1:14:0822/153830:WARNING:video_capture_input.cc(79)] Same/old NTP timestamp (3680861906110 <= 3680861906110) for incoming frame. Dropping.
[1:14:0822/153830:WARNING:video_capture_input.cc(79)] Same/old NTP timestamp (3680861906042 <= 3680861906042) for incoming frame. Dropping.

Original issue's description:
> Delete the class WebRtcVideoCapturerAdapter::MediaVideoFrameFactory
>
> Instead, use the AdaptFrame and OnFrame methods of the VideoCapturer
> base class.
>
> This cl also applies the new timestamp aligner logic, to translate
> Chrome's camera timestamps into the timescale of rtc::TimeMicros(). No
> other change in behavior is intended.
>
> BUG=webrtc:5682, webrtc:5740, 516700
>
> Committed: https://crrev.com/5b9a4b339447b033ca52244a02c0bef17067385f
> Cr-Commit-Position: refs/heads/master@{#413093}

TBR=perkj@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:5682, webrtc:5740, 516700

Review-Url: https://codereview.chromium.org/2263183002
Cr-Commit-Position: refs/heads/master@{#413444}

content/renderer/media/webrtc/webrtc_video_capturer_adapter.h

@@ -15,7 +15,6 @@
 #include "content/common/content_export.h"
 #include "media/base/video_capture_types.h"
 #include "media/base/video_frame.h"
-#include "media/base/video_frame_pool.h"
 #include "third_party/webrtc/media/base/videocapturer.h"
 
 namespace content {
@@ -57,7 +56,7 @@ class CONTENT_EXPORT WebRtcVideoCapturerAdapter
   const bool is_screencast_;
   bool running_;
 
-  media::VideoFramePool scaled_frame_pool_;
+  class MediaVideoFrameFactory;
 
   DISALLOW_COPY_AND_ASSIGN(WebRtcVideoCapturerAdapter);
 };

content/renderer/media/webrtc/webrtc_video_capturer_adapter_unittest.cc

@@ -11,18 +11,17 @@
 namespace content {
 
 class WebRtcVideoCapturerAdapterTest
-    : public rtc::VideoSinkInterface<cricket::VideoFrame>,
+    : public sigslot::has_slots<>,
       public ::testing::Test {
  public:
   WebRtcVideoCapturerAdapterTest()
       : adapter_(false),
         output_frame_width_(0),
         output_frame_height_(0) {
-    adapter_.AddOrUpdateSink(this, rtc::VideoSinkWants());
-  }
-  ~WebRtcVideoCapturerAdapterTest() override {
-    adapter_.RemoveSink(this);
+    adapter_.SignalFrameCaptured.connect(
+        this, &WebRtcVideoCapturerAdapterTest::OnFrameCaptured);
   }
+  ~WebRtcVideoCapturerAdapterTest() override {}
 
   void TestSourceCropFrame(int capture_width,
                            int capture_height,
@@ -43,11 +42,11 @@ class WebRtcVideoCapturerAdapterTest
     EXPECT_EQ(natural_width, output_frame_width_);
     EXPECT_EQ(natural_height, output_frame_height_);
   }
-
-  // rtc::VideoSinkInterface
-  void OnFrame(const cricket::VideoFrame& frame) override {
-    output_frame_width_ = frame.width();
-    output_frame_height_ = frame.height();
+ protected:
+  void OnFrameCaptured(cricket::VideoCapturer* capturer,
+                       const cricket::CapturedFrame* frame) {
+    output_frame_width_ = frame->width;
+    output_frame_height_ = frame->height;
   }
 
  private: