Add DesktopFrame rotation functions

webrtc/modules/desktop_capture/desktop_frame.cc

Index: webrtc/modules/desktop_capture/desktop_frame.cc
diff --git a/webrtc/modules/desktop_capture/desktop_frame.cc b/webrtc/modules/desktop_capture/desktop_frame.cc
index dfc0928b6631b83522e498dd07224c1c59e2bf8b..a1ee33b2c52c888522c2be804c94e1ee8e9bd111 100644
--- a/webrtc/modules/desktop_capture/desktop_frame.cc
+++ b/webrtc/modules/desktop_capture/desktop_frame.cc
@@ -57,6 +57,44 @@ uint8_t* DesktopFrame::GetFrameDataAtPos(const DesktopVector& pos) const {
   return data() + stride() * pos.y() + DesktopFrame::kBytesPerPixel * pos.x();
 }
 
+bool DesktopFrame::DataEquals(const DesktopFrame& other) const {
+  if (!size().equals(other.size())) {
+    return false;
+  }
+  if (stride() == other.stride() &&
+      stride() == DesktopFrame::kBytesPerPixel * size().width()) {
+    return memcmp(data(), other.data(), stride() * size().height()) == 0;
+  }
+
+  const uint8_t* my_array = data();
+  const uint8_t* other_array = other.data();
+  for (int i = 0; i < size().height(); i++) {
+    const uint8_t* my_this_line = my_array;
+    const uint8_t* other_this_line = other_array;
+    for (int j = 0; j < size().width(); j++) {
+      if (memcmp(my_this_line, other_this_line, kBytesPerPixel)
+          != 0) {
+        return false;
+      }
+      my_this_line += kBytesPerPixel;
+      other_this_line += kBytesPerPixel;
+    }
+    my_array += stride();
+    other_array += other.stride();
+  }
+
+  return true;
+}
+
+void DesktopFrame::Paint(DesktopVector pos, RgbaColor color) {
+  RTC_DCHECK(DesktopRect::MakeSize(size()).Contains(pos));
+  *reinterpret_cast<uint32_t*>(GetFrameDataAtPos(pos)) = color.ToUInt32();
+}
+
+void DesktopFrame::Clear() {
+  memset(data(), 0, stride() * size().height());
+}
+
 BasicDesktopFrame::BasicDesktopFrame(DesktopSize size)
     : DesktopFrame(size, kBytesPerPixel * size.width(),
                    new uint8_t[kBytesPerPixel * size.width() * size.height()],