Revert of Add compositor support for half-float RGBA buffers and textures

cc/output/gl_renderer.cc

Index: cc/output/gl_renderer.cc
diff --git a/cc/output/gl_renderer.cc b/cc/output/gl_renderer.cc
index 12f415b255b772bcc11526f0abdce06826039b4f..add015fe1aa5c15ffc196275cd842ff86b8eca36 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -427,12 +427,6 @@
 bool GLRenderer::CanPartialSwap() {
   auto* context_provider = output_surface_->context_provider();
   return context_provider->ContextCapabilities().post_sub_buffer;
-}
-
-ResourceFormat GLRenderer::BackbufferFormat() const {
-  // TODO(ccameron): If we are targeting high bit depth or HDR, we should use
-  // RGBA_F16 here.
-  return resource_provider_->best_texture_format();
 }
 
 void GLRenderer::DidChangeVisibility() {
@@ -913,7 +907,7 @@
   // CopyTexImage2D fails when called on a texture having immutable storage.
   device_background_texture->Allocate(
       bounding_rect.size(), ResourceProvider::TEXTURE_HINT_DEFAULT,
-      BackbufferFormat(), frame->device_color_space);
+      resource_provider_->best_texture_format(), frame->device_color_space);
   {
     ResourceProvider::ScopedWriteLockGL lock(
         resource_provider_, device_background_texture->id(), false);