chore: bump chromium to 7d4ac110045b7647fa8a81f5f0709 (master) (#24970)

* chore: bump chromium in DEPS to 760c905ccca34d8ed83c54f6a42c42a375792a6b

* chore: update patches

- Introduce WebContentsObserverList to encapsulate common behaviour
  2343269
- DumpAccTree mac testing: refactor tree formatter logic to make it
suitable for nested attribute calls
  2274545
- Fix FontPlatformDataMacTest.VariableOpticalSizingThreshold for Big Sur
  2351299

* chore: bump chromium in DEPS to b04584161e07d4ac110045b7647fa8a81f5f0709

* chore: update patches

* [printing] Move printing::MarginType to //printing/mojom/print.mojom

2341222

Co-authored-by: deepak1556 <hop2deep@gmail.com>

patches/v8/expose_mksnapshot.patch

@@ -6,10 +6,10 @@ Subject: expose_mksnapshot.patch
 Needed in order to target mksnapshot for mksnapshot zip.
 
 diff --git a/BUILD.gn b/BUILD.gn
-index 4886a78cd7737f70ee002d31758dad807aad604d..4d5728cb16bb87f2b01f935ba2173b19968983d2 100644
+index b6873dbe4dbbdd8c225fbba39be1f091f8a048ec..b51e174c2943f14a0c234eedc533e0366303808d 100644
 --- a/BUILD.gn
 +++ b/BUILD.gn
-@@ -4428,7 +4428,6 @@ if (current_toolchain == v8_generator_toolchain) {
+@@ -4422,7 +4422,6 @@ if (current_toolchain == v8_generator_toolchain) {
  
  if (current_toolchain == v8_snapshot_toolchain) {
    v8_executable("mksnapshot") {