Remove android x86 codepaths that are unused.

[reidbaker]

The tool has removed x86 support in support of dart removing x86 support as of #169884.

Audit android build code and remove codepaths for x86 as needed.

https://github.com/flutter/flutter/blob/master/packages/flutter_tools/gradle/src/main/kotlin/FlutterPlugin.kt#L105
https://github.com/flutter/flutter/blob/master/packages/flutter_tools/gradle/src/main/kotlin/FlutterPluginConstants.kt#L13

Edited:

More code locations:

Code pointers for future contributors.

flutter/engine/src/build/toolchain/linux/BUILD.gn

Line 137 in e9e989b

gcc_toolchain("x86") {

flutter/engine/src/flutter/sky/tools/flutter_gdb

Line 75 in e9e989b

if abi == 'x86':

flutter/engine/src/flutter/assets/native_assets.cc

Line 16 in e9e989b

#elif defined(FML_ARCH_CPU_X86)

flutter/engine/src/build/toolchain/android/BUILD.gn

Line 129 in e9e989b

android_toolchains_helper("x86") {

flutter/engine/src/flutter/tools/engine_tool/lib/src/flutter_tool_interop/target_platform.dart

Line 29 in e9e989b

/// Android x86.

flutter/packages/flutter_tools/lib/src/emulator.dart

Line 141 in e9e989b

' sdkmanager "system-images;android-27;google_apis_playstore;x86"',

flutter/engine/src/flutter/common/config.gni

Line 119 in e9e989b

# gen_snapshot), the host_cpu is set to x86. However, the correct prebuilt

flutter/engine/src/flutter/tools/engine_tool/lib/src/commands/run_command.dart

Line 235 in e9e989b

TargetPlatform.androidX86 => 'android_${mode}_x86',

This is just a warning.

flutter/packages/flutter_tools/lib/src/android/gradle.dart

Line 134 in e9e989b

const String androidX86DeprecationWarning =

ci configs

flutter/engine/src/flutter/ci/builders/linux_android_emulator.json

Line 84 in e9e989b

"--android-cpu=x86",

flutter/engine/src/flutter/ci/builders/linux_android_debug_engine.json

Line 108 in e9e989b

"name": "ci/android_debug_x86",

flutter/engine/src/flutter/shell/platform/android/BUILD.gn

Line 697 in e9e989b

if (target_cpu != "x86") {

Impeller documenation

flutter/engine/src/flutter/impeller/toolkit/interop/README.md

Line 39 in e9e989b

| x86 | | | android-x86 | |

[jmagman]

Also check the packages repo:
https://github.com/flutter/packages/blob/974f1522ee03b40e0476c4560267af2a20e83906/script/tool/lib/src/native_test_command.dart#L403

I added a section to the next technical blog post to mention this.

And it looks like it's already not in the supported platforms table https://docs.flutter.dev/reference/supported-platforms