[Impeller] Revert support for multi-arch shader archives. (#53158)

This was never fully wired up and we never ended up needing this as there is only still on backend per platform. Earlier, we expected to have both GLES and Vulkan on Android.

Reverts 2251b87 and 502755d with fixups.

Author: chinmaygarde

ci/licenses_golden/licenses_flutter

@@ -42902,11 +42902,6 @@ ORIGIN: ../../../flutter/impeller/scene/shaders/unlit.frag + ../../../flutter/LI
 ORIGIN: ../../../flutter/impeller/scene/shaders/unskinned.vert + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/scene/skin.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/scene/skin.h + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/shader_archive/multi_arch_shader_archive.cc + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/shader_archive/multi_arch_shader_archive.fbs + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/shader_archive/multi_arch_shader_archive.h + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/shader_archive/multi_arch_shader_archive_writer.cc + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/shader_archive/multi_arch_shader_archive_writer.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/shader_archive/shader_archive.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/shader_archive/shader_archive.fbs + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/shader_archive/shader_archive.h + ../../../flutter/LICENSE
@@ -45771,11 +45766,6 @@ FILE: ../../../flutter/impeller/scene/shaders/unlit.frag
 FILE: ../../../flutter/impeller/scene/shaders/unskinned.vert
 FILE: ../../../flutter/impeller/scene/skin.cc
 FILE: ../../../flutter/impeller/scene/skin.h
-FILE: ../../../flutter/impeller/shader_archive/multi_arch_shader_archive.cc
-FILE: ../../../flutter/impeller/shader_archive/multi_arch_shader_archive.fbs
-FILE: ../../../flutter/impeller/shader_archive/multi_arch_shader_archive.h
-FILE: ../../../flutter/impeller/shader_archive/multi_arch_shader_archive_writer.cc
-FILE: ../../../flutter/impeller/shader_archive/multi_arch_shader_archive_writer.h
 FILE: ../../../flutter/impeller/shader_archive/shader_archive.cc
 FILE: ../../../flutter/impeller/shader_archive/shader_archive.fbs
 FILE: ../../../flutter/impeller/shader_archive/shader_archive.h

impeller/README.md

@@ -175,9 +175,6 @@ flowchart TD
 
     spirv -- Reflector --> cxx_sources[C++ Sources]
     cxx_sources -- Ninja Build --> cxx_library[C++ Library]
-
-    vulkan_shader_archive -- Multi Arch Archiver --> multi_arch_archive[Multi Architecture Archive]
-    gles_shader_archive -- Multi Arch Archiver --> multi_arch_archive
 ```
 
 ## Try Impeller in Flutter

impeller/renderer/backend/gles/shader_library_gles.cc

@@ -10,7 +10,6 @@
 #include "impeller/base/config.h"
 #include "impeller/base/validation.h"
 #include "impeller/renderer/backend/gles/shader_function_gles.h"
-#include "impeller/shader_archive/multi_arch_shader_archive.h"
 #include "impeller/shader_archive/shader_archive.h"
 
 namespace impeller {
@@ -69,13 +68,12 @@ ShaderLibraryGLES::ShaderLibraryGLES(
     return true;
   };
   for (auto library : shader_libraries) {
-    auto gles_archive = MultiArchShaderArchive::CreateArchiveFromMapping(
-        std::move(library), ArchiveRenderingBackend::kOpenGLES);
-    if (!gles_archive || !gles_archive->IsValid()) {
-      VALIDATION_LOG << "Could not construct shader library.";
+    auto blob_library = ShaderArchive{std::move(library)};
+    if (!blob_library.IsValid()) {
+      VALIDATION_LOG << "Could not construct blob library for shaders.";
       return;
     }
-    gles_archive->IterateAllShaders(iterator);
+    blob_library.IterateAllShaders(iterator);
   }
 
   functions_ = functions;

impeller/renderer/backend/vulkan/shader_library_vk.cc

@@ -10,7 +10,6 @@
 #include "flutter/fml/trace_event.h"
 #include "impeller/renderer/backend/vulkan/context_vk.h"
 #include "impeller/renderer/backend/vulkan/shader_function_vk.h"
-#include "impeller/shader_archive/multi_arch_shader_archive.h"
 #include "impeller/shader_archive/shader_archive.h"
 
 namespace impeller {
@@ -68,13 +67,12 @@ ShaderLibraryVK::ShaderLibraryVK(
     return true;
   };
   for (const auto& library_data : shader_libraries_data) {
-    auto vulkan_library = MultiArchShaderArchive::CreateArchiveFromMapping(
-        library_data, ArchiveRenderingBackend::kVulkan);
-    if (!vulkan_library || !vulkan_library->IsValid()) {
-      VALIDATION_LOG << "Could not construct Vulkan shader library archive.";
+    auto blob_library = ShaderArchive{library_data};
+    if (!blob_library.IsValid()) {
+      VALIDATION_LOG << "Could not construct shader blob library.";
       return;
     }
-    vulkan_library->IterateAllShaders(iterator);
+    blob_library.IterateAllShaders(iterator);
   }
 
   if (!success) {

impeller/shader_archive/BUILD.gn

@@ -11,20 +11,13 @@ config("shader_archive_config") {
 }
 
 flatbuffers("shader_archive_flatbuffers") {
-  flatbuffers = [
-    "shader_archive.fbs",
-    "multi_arch_shader_archive.fbs",
-  ]
+  flatbuffers = [ "shader_archive.fbs" ]
   public_configs = [ ":shader_archive_config" ]
   public_deps = [ "//flutter/third_party/flatbuffers" ]
 }
 
 impeller_component("shader_archive") {
   sources = [
-    "multi_arch_shader_archive.cc",
-    "multi_arch_shader_archive.h",
-    "multi_arch_shader_archive_writer.cc",
-    "multi_arch_shader_archive_writer.h",
     "shader_archive.cc",
     "shader_archive.h",
     "shader_archive_types.h",