refactor: move text-to-speech out of chromium_src (#15024)

* chore: add tts patch and buildflag, makes tts work again

* chore: add tts patch and buildflag, makes tts work again

* fix: make things compile

* build: add relevant tts files for linux

* fix: update patch and patch description, should now compile on mac

* build: move chrome specific sources under chromium_src:chrome target

* build: enable_extensions again

We are depending on them, check `//electron/chromium_src:chrome` target
for more info.

* fix: update tts.patch to receive notifications about browser context destruction

* fix: extend browser process from chrome layer

The global state g_browser_process is shared between //chrome
and //electron.

* spec: add basic speech synthesis test

* spec: skip speech tests on ci

* build: fix compilation on windows

buildflags/BUILD.gn

@@ -15,6 +15,7 @@ buildflag_header("buildflags") {
     "ENABLE_VIEW_API=$enable_view_api",
     "ENABLE_PEPPER_FLASH=$enable_pepper_flash",
     "ENABLE_PDF_VIEWER=$enable_pdf_viewer",
+    "ENABLE_TTS=$enable_tts",
     "OVERRIDE_LOCATION_PROVIDER=$enable_fake_location_provider",
   ]
 }

buildflags/buildflags.gni

@@ -14,6 +14,8 @@ declare_args() {
 
   enable_pdf_viewer = false
 
+  enable_tts = true
+
   # Provide a fake location provider for mocking
   # the geolocation responses. Disable it if you
   # need to test with chromium's location provider.