Revert of Mac Video Capture AVFoundation: Calculate compressed frame size for MJPEG. (patchset #2 id:20001 of https://codereview.chromium.org/912293005/)

Reason for revert:
An improved version of ValidateJpeg in libyuv has been rolled into chromium and this CL is no longer needed.

Original issue's description:
> Mac Video Capture AVFoundation: Calculate compressed frame size for MJPEG.
>
> The frame size we receive from AVFoundation is sometimes excessive, e.g. the size of the uncompressed frame. For example, for a JPEG YUV422, the reported size might be 1280*720*2 = 1.8MB, while the actual compressed data is only 260kB.
>
> In these cases, libyuv::MJPGToI420 spends a lot of time in libyuv::ValidateJpeg, as much as 25%. The reason for this is that ValidateJpeg starts at the end of the buffer and loops backwards looking for the End Of Image (EOI) marker.
>
> This CL tries to optimize these cases by finding the EOI by looping forwards instead of backwards, and reporting the actual frame size to libyuv::MJPGToI420.
>
> BUG=346634,460497
>
> Committed: https://crrev.com/dc556d2b54354adc95ee5474600f469f7ae65692
> Cr-Commit-Position: refs/heads/master@{#317333}

TBR=perkj@chromium.org,mcasas@chromium.org,tommi@chromium.org,torbjorng@google.com,torbjorng@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=346634,460497

Review URL: https://codereview.chromium.org/1089173003

Cr-Commit-Position: refs/heads/master@{#325211}

1 files changed, 0 insertions, 27 deletions

diff --git a/media/video/capture/mac/video_capture_device_avfoundation_mac.mm b/media/video/capture/mac/video_capture_device_avfoundation_mac.mm
index 6d71ef8..f3c7ca7 100644
--- a/media/video/capture/mac/video_capture_device_avfoundation_mac.mm
+++ b/media/video/capture/mac/video_capture_device_avfoundation_mac.mm
@@ -6,8 +6,6 @@
 
 #import <CoreVideo/CoreVideo.h>
 
-#include <cstring>  // For memchr.
-
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
 #include "media/video/capture/mac/video_capture_device_mac.h"
@@ -32,21 +30,6 @@ media::VideoPixelFormat FourCCToChromiumPixelFormat(FourCharCode code) {
   }
 }
 
-// TODO(magjed): Remove this when Chromium has the latest libyuv version.
-// Returns frame size by finding the End Of Image marker, or 0 if not found.
-size_t JpegFrameSize(const char* sample, size_t sampleSize) {
-  // Jump to next marker (0xff), check for End Of Image (0xd9), repeat.
-  const char* end = sample + sampleSize - 1;
-  for (const char* it = sample;
-       (it = static_cast<const char*>(memchr(it, 0xff, end - it)));
-       ++it) {
-    if (it[1] == static_cast<char>(0xd9))
-      return 2 + (it - sample);
-  }
-  DLOG(WARNING) << "JPEG End Of Image (EOI) marker not found.";
-  return 0;
-}
-
 @implementation VideoCaptureDeviceAVFoundation
 
 #pragma mark Class methods
@@ -323,16 +306,6 @@ size_t JpegFrameSize(const char* sample, size_t sampleSize) {
       // Expect the MJPEG data to be available as a contiguous reference, i.e.
       // not covered by multiple memory blocks.
       CHECK_EQ(lengthAtOffset, frameSize);
-
-      // TODO(magjed): Remove this when Chromium has the latest libyuv version.
-      // If |frameSize| is suspiciously high (>= 8 bpp), calculate the actual
-      // size by finding the end of image marker. The purpose is to speed up the
-      // jpeg decoding in the browser.
-      if (static_cast<int>(frameSize) >= dimensions.width * dimensions.height)
-        frameSize = JpegFrameSize(baseAddress, frameSize);
-
-      if (frameSize == 0)
-        return;
     }
   } else {
     videoFrame = CoreMediaGlue::CMSampleBufferGetImageBuffer(sampleBuffer);