build: move libcc patches to electron repo (#14104)

In the GN build, libchromiumcontent is no longer a distinct library, but
merely a container for a set of scripts and patches. Maintaining those
patches in a separate repository is tedious and error-prone, so merge
them into the main repo.

Once this is merged and GN is the default way to build Electron, the
libchromiumcontent repository can be archived.

patches/common/chromium/blink_local_frame.patch

@@ -0,0 +1,26 @@
+diff --git a/third_party/blink/renderer/core/frame/local_frame.cc b/third_party/blink/renderer/core/frame/local_frame.cc
+index 97a5393d40b4..04f88dd2ea15 100644
+--- a/third_party/blink/renderer/core/frame/local_frame.cc
++++ b/third_party/blink/renderer/core/frame/local_frame.cc
+@@ -303,10 +303,6 @@ void LocalFrame::Detach(FrameDetachType type) {
+   }
+   CHECK(!view_ || !view_->IsAttached());
+ 
+-  // This is the earliest that scripting can be disabled:
+-  // - FrameLoader::Detach() can fire XHR abort events
+-  // - Document::Shutdown() can dispose plugins which can run script.
+-  ScriptForbiddenScope forbid_script;
+   if (!Client())
+     return;
+ 
+@@ -316,6 +312,10 @@ void LocalFrame::Detach(FrameDetachType type) {
+   // Notify ScriptController that the frame is closing, since its cleanup ends
+   // up calling back to LocalFrameClient via WindowProxy.
+   GetScriptController().ClearForClose();
++  // This is the earliest that scripting can be disabled:
++  // - FrameLoader::Detach() can fire XHR abort events
++  // - Document::Shutdown() can dispose plugins which can run script.
++  ScriptForbiddenScope forbid_script;
+ 
+   // TODO(crbug.com/729196): Trace why LocalFrameView::DetachFromLayout crashes.
+   CHECK(!view_->IsAttached());