Reland "Enable JDK library desugaring by default" (take 2)

This depends on the L8 determinism fix: https://chromium-review.googlesource.com/c/chromium/src/+/2519098

Enables JDK library desugaring only for the "default" channel for now. It can be enabled globally after M88 branch.

This is a reland of 8699ff59

Original change's description:
> Enable JDK library desugaring by default
>
> Bug: 1056751
> Change-Id: Id517413e180ad7cc2f7688d47038587f2a3ecb5e
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2458853
> Reviewed-by: Andrew Grieve <agrieve@chromium.org>
> Commit-Queue: Ian Wells <iwells@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#817575}

Bug: 1056751
Change-Id: Ib281d063b814ee629a3633868eb1efe70a153379
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2519888
Commit-Queue: Ian Wells <iwells@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Auto-Submit: Ian Wells <iwells@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826558}

build/config/android/config.gni

@@ -6,6 +6,9 @@
 # |is_chromeos| is true in a LaCrOS build.
 import("//build/config/chromeos/ui_mode.gni")
 
+# TODO(iwells) remove when android_channel is no longer needed for enable_jdk_library_desugaring
+import("//build/config/android/channel.gni")
+
 # This file contains common system config stuff for the Android build.
 
 # NOTE: Because Chrome OS builds may depend on targets built with the Android
@@ -255,7 +258,8 @@ if (is_android || is_chromeos ||
 
     # Enables Java library desugaring.
     # This will cause an extra classes.dex file to appear in every apk.
-    enable_jdk_library_desugaring = false
+    # TODO(iwells): change to true after M88 branch point
+    enable_jdk_library_desugaring = android_channel == "default"
   }
 
   # Host stuff -----------------------------------------------------------------

third_party/accessibility_test_framework/BUILD.gn

@@ -10,7 +10,6 @@ android_java_prebuilt("accessibility_test_framework_java") {
   # Uses wrong version of proto (not protolite).
   # Disable these to avoid build warnings.
   enable_bytecode_checks = false
-  enable_desugar = false
 
   jar_path = "lib/accessibility-test-framework.jar"
   deps = [

third_party/byte_buddy/BUILD.gn

@@ -8,7 +8,6 @@ java_prebuilt("byte_buddy_java") {
   testonly = true
   supports_android = true
   enable_bytecode_checks = false
-  enable_desugar = false
   jar_path = "lib/byte-buddy.jar"
 }
 
@@ -16,7 +15,6 @@ java_prebuilt("byte_buddy_agent_java") {
   testonly = true
   supports_android = true
   enable_bytecode_checks = false
-  enable_desugar = false
   jar_path = "lib/byte-buddy-agent.jar"
 }
 
@@ -27,14 +25,12 @@ java_prebuilt("dx_25_0_2_java") {
   supports_android = true
   requires_android = true
   no_build_hooks = true
-  enable_desugar = false
   jar_path = "android_sdk_build_tools_25_0_2/build-tools/25.0.2/lib/dx.jar"
 }
 
 android_java_prebuilt("byte_buddy_android_java") {
   testonly = true
   enable_bytecode_checks = false
-  enable_desugar = false
   deps = [ ":dx_25_0_2_java" ]
   proguard_configs = [ "//third_party/byte_buddy/proguard.flags" ]
   jar_path = "lib/byte-buddy-android.jar"

third_party/google-truth/BUILD.gn

@@ -9,7 +9,6 @@ java_prebuilt("google_truth_java") {
 
   # Uses the difflib package, which doesn't exist in third_party.
   enable_bytecode_checks = false
-  enable_desugar = false
   supports_android = true
 
   # requires_android because of dependency on guava_android.