gyp: drop unused build system

Chromium moved to GN a long time ago, and CrOS has never used this.
Let's remove one of the build systems to make it easier on people.
Especially since the GYP tool is completely unmaintained now.

Change-Id: I0371ca1427811f307dc30f88ed6d1bf61d7fab89
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/4054941
Reviewed-by: Mark Mentovai <mark@chromium.org>

DEPS

@@ -43,11 +43,6 @@ deps = {
     "https://github.com/google/protobuf.git" +
       "@cb6dd4ef5f82e41e06179dcd57d3b1d9246ad6ac",
 
-  # GYP project generator.
-  "src/src/tools/gyp":
-    "https://chromium.googlesource.com/external/gyp/" +
-      "@324dd166b7c0b39d513026fa52d6280ac6d56770",
-
   # Linux syscall support.
   "src/src/third_party/lss":
     "https://chromium.googlesource.com/linux-syscall-support/" +
@@ -61,24 +56,3 @@ hooks = [
                "src/DEPS", "src/default.xml"],
   },
 ]
-
-hooks_os = {
-  'win': [
-    {
-      # TODO(chrisha): Fix the GYP files so that they work without
-      # --no-circular-check.
-      "pattern": ".",
-      "action": ["python",
-                 "src/src/tools/gyp/gyp_main.py",
-                 "--no-circular-check",
-                 "src/src/client/windows/breakpad_client.gyp"],
-    },
-    {
-      # XXX: this and above should all be wired into build/all.gyp ?
-      "action": ["python",
-                 "src/src/tools/gyp/gyp_main.py",
-                 "--no-circular-check",
-                 "src/src/tools/windows/tools_windows.gyp"],
-    },
-  ],
-}