Use Dawn's copy of GLFW since it manages its build file.

This is to:
 - Add Wayland support to Dawn's swapchains, which requires to
 - Upgrade GLFW to detect X11 vs. Wayland in testing, which requires to
 - Roll GLFW to a version that supports Wayland, which requires to
 - Update GLFW's BUILD.gn file that live in Dawn's repo.

Bug: dawn:1246
Change-Id: I7cf80ea27756a46f2db495ece26733b57be81541
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3663229
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Auto-Submit: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1007358}

DEPS

@@ -1025,9 +1025,6 @@ deps = {
   'src/third_party/highway/src':
     Var('chromium_git') + '/external/github.com/google/highway.git' + '@' + Var('highway_revision'),
 
-  'src/third_party/glfw/src':
-    Var('chromium_git') + '/external/github.com/glfw/glfw.git@' +  '94773111300fee0453844a4c9407af7e880b4df8',
-
   'src/third_party/apache-portable-runtime/src': {
       'url': Var('chromium_git') + '/external/apache-portable-runtime.git' + '@' + 'c3f11fcd86b42922834cae91103cf068246c6bb6',
       'condition': 'checkout_android',
@@ -4689,7 +4686,8 @@ hooks = [
 recursedeps = [
   # ANGLE manages DEPS that it also owns the build files for, such as dEQP.
   'src/third_party/angle',
-  # Dawn needs CTS from its DEPS
+  # Dawn manages DEPS for its copy of the WebGPU CTS as well as GLFW for which
+  # it has build files.
   'src/third_party/dawn',
   'src/third_party/openscreen/src',
   'src/third_party/vulkan-deps',

build_overrides/dawn.gni

@@ -4,7 +4,7 @@
 
 # The paths to Dawn's dependencies
 dawn_angle_dir = "//third_party/angle"
-dawn_glfw_dir = "//third_party/glfw/src"
+dawn_glfw_dir = "//third_party/dawn/third_party/glfw"
 dawn_googletest_dir = "//third_party/googletest/src"
 dawn_jinja2_dir = "//third_party/jinja2"
 dawn_jsoncpp_dir = "//third_party/jsoncpp"