Revert "Add support for GCS deps"

This reverts commit 3eedee7b55.

Reason for revert: https://buganizer.corp.google.com/issues/324418194#comment7

Original change's description:
> Add support for GCS deps
>
> Also take out GCS calling logic from download_google_storage and
> into call_google_storage.
>
> GCS deps look like:
>    'src/third_party/node/linux': {
>        'dep_type': 'gcs',
>        'condition': 'checkout_linux',
>        'bucket': 'chromium-nodejs/20.11.0',
>        'object_name': '46795170ff5df9831955f163f6966abde581c8af',
>        'sha256sum': '887504c37404898ca41b896f448ee6d7fc24179d8fb6a4b79d028ab7e1b7153d',
>    },
>
>    'src/third_party/llvm-build/Release+Asserts': {
>        'dep_type': 'gcs',
>        'condition': 'checkout_linux',
>        'bucket': 'chromium-browser-clang',
>        'object_name': 'Linux_x64/clang-llvmorg-18-init-17730-gf670112a-2.tar.xz',
>        'sha256sum': '1e46df9b4e63c074064d75646310cb76be2f19815997a8486987189d80f991e8',
>    },
>
> Example directory for src/third_party/node/linux after gclient sync:
> - tar_file.gz is the downloaded file from GCS.
> - node_linux_x64/ is extracted in its path.
> - `hash` contains the sha of GCS filename.
> ```
> chromium/src/ ->
>    third_party/node/linux/ ->
>        hash, tar_file.gz, node_linux_x64/
> ```
>
> Bug: b/324418194
> Change-Id: Ibcbbff27e211f194ddb8a08494af56570a84a12b
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5299722
> Commit-Queue: Stephanie Kim <kimstephanie@google.com>
> Reviewed-by: Joanna Wang <jojwang@chromium.org>

Bug: b/324418194
Change-Id: Ie74df90065c1fea087b240d98005b9d9b4f44411
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5336079
Commit-Queue: Stephanie Kim <kimstephanie@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Josip Sokcevic <sokcevic@chromium.org>

git_cache.py

@@ -16,7 +16,7 @@ import threading
 import time
 import urllib.parse
 
-from call_google_storage import Gsutil
+from download_from_google_storage import Gsutil
 import gclient_utils
 import lockfile
 import metrics