[chromecast] Remove reading display-rotation

Remove reading from command line to obtain cast display rotation from
CastDisplayConfigurator. The display rotation is now read from kernel
for https://chromium-review.googlesource.com/c/chromium/src/+/2229725

Bug: b/77900197
Test: build and run on device.
Change-Id: I8d1f4c49c4a0ae12ea01c982d72af7f2c8617f92
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2252938Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Commit-Queue: Yuanyao Zhong <yyzhong@google.com>
Cr-Commit-Position: refs/heads/master@{#779992}

chromecast/browser/cast_display_configurator.cc

@@ -30,7 +30,6 @@ namespace {
 constexpr int64_t kStubDisplayId = 1;
 constexpr char kCastGraphicsHeight[] = "cast-graphics-height";
 constexpr char kCastGraphicsWidth[] = "cast-graphics-width";
-constexpr char kDisplayRotation[] = "display-rotation";
 
 gfx::Size GetDefaultScreenResolution() {
 #if BUILDFLAG(IS_CAST_AUDIO_ONLY)
@@ -64,20 +63,6 @@ gfx::Size GetScreenResolution() {
   return GetDefaultScreenResolution();
 }
 
-display::Display::Rotation GetRotationFromCommandLine() {
-  std::string rotation =
-      base::CommandLine::ForCurrentProcess()->GetSwitchValueNative(
-          kDisplayRotation);
-  if (rotation == "90")
-    return display::Display::ROTATE_90;
-  else if (rotation == "180")
-    return display::Display::ROTATE_180;
-  else if (rotation == "270")
-    return display::Display::ROTATE_270;
-  else
-    return display::Display::ROTATE_0;
-}
-
 display::Display::Rotation RotationFromPanelOrientation(
     display::PanelOrientation orientation) {
   switch (orientation) {
@@ -145,7 +130,7 @@ void CastDisplayConfigurator::OnConfigurationChanged() {
 void CastDisplayConfigurator::ConfigureDisplayFromCommandLine() {
   const gfx::Size size = GetScreenResolution();
   UpdateScreen(kStubDisplayId, gfx::Rect(size), GetDeviceScaleFactor(size),
-               GetRotationFromCommandLine());
+               display::Display::ROTATE_0);
 }
 
 void CastDisplayConfigurator::SetColorMatrix(