Add unit tests for RTCCVPixelBuffer and ObjCVideoTrackSource.

This CL also fixes a couple of bugs found in the toI420 method for
RTCCVPixelBuffers backed by RGB CVPixelBuffers.

Bug: webrtc:9007
Change-Id: I19ab8177f4b124a503cfda9f0166bd960f668982
Reviewed-on: https://webrtc-review.googlesource.com/64940
Commit-Queue: Anders Carlsson <andersc@webrtc.org>
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22656}

sdk/objc/Framework/UnitTests/frame_buffer_helpers.mm

@@ -0,0 +1,122 @@
+/*
+ *  Copyright 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "sdk/objc/Framework/UnitTests/frame_buffer_helpers.h"
+
+#include "third_party/libyuv/include/libyuv.h"
+
+void DrawGradientInRGBPixelBuffer(CVPixelBufferRef pixelBuffer) {
+  CVPixelBufferLockBaseAddress(pixelBuffer, kCVPixelBufferLock_ReadOnly);
+  void* baseAddr = CVPixelBufferGetBaseAddress(pixelBuffer);
+  size_t width = CVPixelBufferGetWidth(pixelBuffer);
+  size_t height = CVPixelBufferGetHeight(pixelBuffer);
+  CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
+  CGContextRef cgContext = CGBitmapContextCreate(baseAddr,
+                                                 width,
+                                                 height,
+                                                 8,
+                                                 CVPixelBufferGetBytesPerRow(pixelBuffer),
+                                                 colorSpace,
+                                                 kCGImageAlphaNoneSkipLast);
+
+  // Create a gradient
+  CGFloat colors[] = {
+      1.0, 1.0, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 1.0, 1.0,
+  };
+  CGGradientRef gradient = CGGradientCreateWithColorComponents(colorSpace, colors, NULL, 4);
+
+  CGContextDrawLinearGradient(
+      cgContext, gradient, CGPointMake(0, 0), CGPointMake(width, height), 0);
+  CGGradientRelease(gradient);
+
+  CGImageRef cgImage = CGBitmapContextCreateImage(cgContext);
+  CGContextRelease(cgContext);
+  CGImageRelease(cgImage);
+  CGColorSpaceRelease(colorSpace);
+
+  CVPixelBufferUnlockBaseAddress(pixelBuffer, kCVPixelBufferLock_ReadOnly);
+}
+
+rtc::scoped_refptr<webrtc::I420Buffer> CreateI420Gradient(int width, int height) {
+  rtc::scoped_refptr<webrtc::I420Buffer> buffer(webrtc::I420Buffer::Create(width, height));
+  // Initialize with gradient, Y = 128(x/w + y/h), U = 256 x/w, V = 256 y/h
+  for (int x = 0; x < width; x++) {
+    for (int y = 0; y < height; y++) {
+      buffer->MutableDataY()[x + y * width] = 128 * (x * height + y * width) / (width * height);
+    }
+  }
+  int chroma_width = buffer->ChromaWidth();
+  int chroma_height = buffer->ChromaHeight();
+  for (int x = 0; x < chroma_width; x++) {
+    for (int y = 0; y < chroma_height; y++) {
+      buffer->MutableDataU()[x + y * chroma_width] = 255 * x / (chroma_width - 1);
+      buffer->MutableDataV()[x + y * chroma_width] = 255 * y / (chroma_height - 1);
+    }
+  }
+  return buffer;
+}
+
+void CopyI420BufferToCVPixelBuffer(rtc::scoped_refptr<webrtc::I420Buffer> i420Buffer,
+                                   CVPixelBufferRef pixelBuffer) {
+  CVPixelBufferLockBaseAddress(pixelBuffer, 0);
+
+  const OSType pixelFormat = CVPixelBufferGetPixelFormatType(pixelBuffer);
+  if (pixelFormat == kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange) {
+    // NV12
+    uint8_t* dstY = static_cast<uint8_t*>(CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 0));
+    const int dstYStride = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 0);
+    uint8_t* dstUV = static_cast<uint8_t*>(CVPixelBufferGetBaseAddressOfPlane(pixelBuffer, 1));
+    const int dstUVStride = CVPixelBufferGetBytesPerRowOfPlane(pixelBuffer, 1);
+
+    libyuv::I420ToNV12(i420Buffer->DataY(),
+                       i420Buffer->StrideY(),
+                       i420Buffer->DataU(),
+                       i420Buffer->StrideU(),
+                       i420Buffer->DataV(),
+                       i420Buffer->StrideV(),
+                       dstY,
+                       dstYStride,
+                       dstUV,
+                       dstUVStride,
+                       i420Buffer->width(),
+                       i420Buffer->height());
+  } else {
+    uint8_t* dst = static_cast<uint8_t*>(CVPixelBufferGetBaseAddress(pixelBuffer));
+    const int bytesPerRow = CVPixelBufferGetBytesPerRow(pixelBuffer);
+
+    if (pixelFormat == kCVPixelFormatType_32BGRA) {
+      // Corresponds to libyuv::FOURCC_ARGB
+      libyuv::I420ToARGB(i420Buffer->DataY(),
+                         i420Buffer->StrideY(),
+                         i420Buffer->DataU(),
+                         i420Buffer->StrideU(),
+                         i420Buffer->DataV(),
+                         i420Buffer->StrideV(),
+                         dst,
+                         bytesPerRow,
+                         i420Buffer->width(),
+                         i420Buffer->height());
+    } else if (pixelFormat == kCVPixelFormatType_32ARGB) {
+      // Corresponds to libyuv::FOURCC_BGRA
+      libyuv::I420ToBGRA(i420Buffer->DataY(),
+                         i420Buffer->StrideY(),
+                         i420Buffer->DataU(),
+                         i420Buffer->StrideU(),
+                         i420Buffer->DataV(),
+                         i420Buffer->StrideV(),
+                         dst,
+                         bytesPerRow,
+                         i420Buffer->width(),
+                         i420Buffer->height());
+    }
+  }
+
+  CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
+}