[Cast] Software encoder support for varying video frame sizes.

media/cast/test/utility/video_utility.cc

Index: media/cast/test/utility/video_utility.cc
diff --git a/media/cast/test/utility/video_utility.cc b/media/cast/test/utility/video_utility.cc
index 9741cd0b118003576becaec4d59897032d83c5f3..ff050dafcb5e3208113d668d8f1bb3774687dc3c 100644
--- a/media/cast/test/utility/video_utility.cc
+++ b/media/cast/test/utility/video_utility.cc
@@ -59,7 +59,11 @@ double I420SSIM(const scoped_refptr<media::VideoFrame>& frame1,
 }
 
 void PopulateVideoFrame(VideoFrame* frame, int start_value) {
-  int height = frame->coded_size().height();
+  const gfx::Size frame_size = frame->coded_size();
+  const int stripe_size =
+      std::max(32, std::min(frame_size.width(), frame_size.height()) / 8) & -2;
+
+  int height = frame_size.height();
   int stride_y = frame->stride(VideoFrame::kYPlane);
   int stride_u = frame->stride(VideoFrame::kUPlane);
   int stride_v = frame->stride(VideoFrame::kVPlane);
@@ -70,24 +74,30 @@ void PopulateVideoFrame(VideoFrame* frame, int start_value) {
 
   // Set Y.
   for (int j = 0; j < height; ++j) {
+    const int stripe_j = (j / stripe_size) * stripe_size;
     for (int i = 0; i < stride_y; ++i) {
-      *y_plane = static_cast<uint8>(start_value + i + j);
+      const int stripe_i = (i / stripe_size) * stripe_size;
+      *y_plane = static_cast<uint8>(start_value + stripe_i + stripe_j);
       ++y_plane;
     }
   }
 
   // Set U.
   for (int j = 0; j < half_height; ++j) {
+    const int stripe_j = (j / stripe_size) * stripe_size;
     for (int i = 0; i < stride_u; ++i) {
-      *u_plane = static_cast<uint8>(start_value + i + j);
+      const int stripe_i = (i / stripe_size) * stripe_size;
+      *u_plane = static_cast<uint8>(start_value + stripe_i + stripe_j);
       ++u_plane;
     }
   }
 
   // Set V.
   for (int j = 0; j < half_height; ++j) {
+    const int stripe_j = (j / stripe_size) * stripe_size;
     for (int i = 0; i < stride_v; ++i) {
-      *v_plane = static_cast<uint8>(start_value + i + j);
+      const int stripe_i = (i / stripe_size) * stripe_size;
+      *u_plane = static_cast<uint8>(start_value + stripe_i + stripe_j);
       ++v_plane;
     }
   }