Switch from .packages to package_config (#106202)

diff --git a/bin/flutter.bat b/bin/flutter.bat
index 06c9a35..87bfde7 100644
--- a/bin/flutter.bat
+++ b/bin/flutter.bat
@@ -51,4 +51,4 @@
 REM Do not use the CALL command in the next line to execute Dart. CALL causes
 REM Windows to re-read the line from disk after the CALL command has finished
 REM regardless of the ampersand chain.
-"%dart%" --disable-dart-dev --packages="%flutter_tools_dir%\.packages" %FLUTTER_TOOL_ARGS% "%snapshot_path%" %* & exit /B !ERRORLEVEL!
+"%dart%" --disable-dart-dev --packages="%flutter_tools_dir%\.dart_tool\package_config.json" %FLUTTER_TOOL_ARGS% "%snapshot_path%" %* & exit /B !ERRORLEVEL!
diff --git a/bin/internal/shared.bat b/bin/internal/shared.bat
index 05cbac1..29456f5 100644
--- a/bin/internal/shared.bat
+++ b/bin/internal/shared.bat
@@ -163,9 +163,9 @@
     POPD
 
     IF "%FLUTTER_TOOL_ARGS%" == "" (
-      "%dart%" --verbosity=error --snapshot="%snapshot_path%" --packages="%flutter_tools_dir%\.packages" --no-enable-mirrors "%script_path%"
+      "%dart%" --verbosity=error --snapshot="%snapshot_path%" --packages="%flutter_tools_dir%\.dart_tool\package_config.json" --no-enable-mirrors "%script_path%"
     ) else (
-      "%dart%" "%FLUTTER_TOOL_ARGS%" --verbosity=error --snapshot="%snapshot_path%" --packages="%flutter_tools_dir%\.packages" "%script_path%"
+      "%dart%" "%FLUTTER_TOOL_ARGS%" --verbosity=error --snapshot="%snapshot_path%" --packages="%flutter_tools_dir%\.dart_tool\package_config.json" "%script_path%"
     )
     IF "%ERRORLEVEL%" NEQ "0" (
       ECHO Error: Unable to create dart snapshot for flutter tool. 1>&2
diff --git a/bin/internal/shared.sh b/bin/internal/shared.sh
index f385229..ab74672 100644
--- a/bin/internal/shared.sh
+++ b/bin/internal/shared.sh
@@ -155,7 +155,7 @@
     pub_upgrade_with_retry
 
     # Compile...
-    "$DART" --verbosity=error --disable-dart-dev $FLUTTER_TOOL_ARGS --snapshot="$SNAPSHOT_PATH" --packages="$FLUTTER_TOOLS_DIR/.packages" --no-enable-mirrors "$SCRIPT_PATH"
+    "$DART" --verbosity=error --disable-dart-dev $FLUTTER_TOOL_ARGS --snapshot="$SNAPSHOT_PATH" --packages="$FLUTTER_TOOLS_DIR/.dart_tool/package_config.json" --no-enable-mirrors "$SCRIPT_PATH"
     echo "$compilekey" > "$STAMP_PATH"
   fi
   # The exit here is extraneous since the function is run in a subshell, but
@@ -222,7 +222,7 @@
     flutter*)
       # FLUTTER_TOOL_ARGS aren't quoted below, because it is meant to be
       # considered as separate space-separated args.
-      exec "$DART" --disable-dart-dev --packages="$FLUTTER_TOOLS_DIR/.packages" $FLUTTER_TOOL_ARGS "$SNAPSHOT_PATH" "$@"
+      exec "$DART" --disable-dart-dev --packages="$FLUTTER_TOOLS_DIR/.dart_tool/package_config.json" $FLUTTER_TOOL_ARGS "$SNAPSHOT_PATH" "$@"
       ;;
     dart*)
       exec "$DART" "$@"