Reland "Remove placeholder Obj-C headers and use angle-bracketed headers."

This is a reland of 37d41eea047799ccca2f09c941870c26ee3ffc0a

Original change's description:
> Reland "Remove placeholder Obj-C headers and use angle-bracketed headers."
>
> This is a reland of 6bfad33fd866e682c871c2ef2172b70b609593d1
>
> Original change's description:
> > Remove placeholder Obj-C headers and use angle-bracketed headers.
> >
> > sdk/objc/Framework/Headers are just a placeholder headers
> > for backward compatibility and I don't think it is really need this for now.
> > Instead, we can generate the framework header in
> > ios/mac_framework_bundle_with_umbrella_header.
> > Also clang supports the -Wquoted-include-in-framework-header warning,
> > and in Xcode 12, it's in Xcode's recommended settings. This warnings
> > can be avoided by replacing double-quoted includes with angle-bracketed
> > includes when generate framework headers.
> >
> > No-Presubmit: True
> > Bug: webrtc:9627, webrtc:11984
> > Change-Id: I3f6258dfa77a5acee669614005b2747feee35e39
> > Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/185920
> > Commit-Queue: Anders Carlsson <andersc@webrtc.org>
> > Reviewed-by: Anders Carlsson <andersc@webrtc.org>
> > Cr-Commit-Position: refs/heads/master@{#32343}
>
> TBR=tommi@webrtc.org, andersc@webrtc.org
>
> No-Presubmit: True
> Bug: webrtc:9627
> Bug: webrtc:11984
> Change-Id: I8f44232f1a70b8ff2ce6a4b4792f0a18472fcec3
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/187280
> Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
> Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#32429}

TBR=tommi@webrtc.org, andersc@webrtc.org

No-Presubmit: True
Bug: webrtc:9627
Bug: webrtc:11984
Change-Id: Ida92b8864dffaea37d3053d3c00381644988b54e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/189781
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32470}
diff --git a/webrtc.gni b/webrtc.gni
index fa3765a..4272e44 100644
--- a/webrtc.gni
+++ b/webrtc.gni
@@ -891,17 +891,39 @@
   # projects. See "mac_framework_bundle_with_umbrella_header".
   template("ios_framework_bundle_with_umbrella_header") {
     forward_variables_from(invoker, [ "output_name" ])
+    this_target_name = target_name
     umbrella_header_path =
-        "$target_gen_dir/$output_name.framework/Headers/$output_name.h"
+        "$target_gen_dir/$output_name.framework/WebRTC/$output_name.h"
+
+    action_foreach("create_bracket_include_headers_$target_name") {
+      script = "//tools_webrtc/apple/copy_framework_header.py"
+      sources = invoker.sources
+      output_name = invoker.output_name
+      outputs = [
+        "$target_gen_dir/$output_name.framework/WebRTC/{{source_file_part}}",
+      ]
+      args = [
+        "--input",
+        "{{source}}",
+        "--output",
+        rebase_path(target_gen_dir, root_build_dir) +
+            "/$output_name.framework/WebRTC/{{source_file_part}}",
+      ]
+    }
 
     ios_framework_bundle(target_name) {
-      forward_variables_from(invoker, "*", [])
-
-      deps += [ ":copy_umbrella_header_$target_name" ]
+      forward_variables_from(invoker, "*", [ "public_headers" ])
+      public_headers = get_target_outputs(
+              ":create_bracket_include_headers_$this_target_name")
+      deps += [
+        ":copy_umbrella_header_$target_name",
+        ":create_bracket_include_headers_$target_name",
+      ]
     }
 
     action("umbrella_header_$target_name") {
-      forward_variables_from(invoker, [ "public_headers" ])
+      public_headers = get_target_outputs(
+              ":create_bracket_include_headers_$this_target_name")
 
       script = "//tools_webrtc/ios/generate_umbrella_header.py"
 
@@ -911,6 +933,7 @@
                rebase_path(umbrella_header_path, root_build_dir),
                "--sources",
              ] + public_headers
+      deps = [ ":create_bracket_include_headers_$this_target_name" ]
     }
 
     copy("copy_umbrella_header_$target_name") {
@@ -957,15 +980,34 @@
         ":copy_framework_headers_$this_target_name",
         ":copy_modulemap_$this_target_name",
         ":copy_umbrella_header_$this_target_name",
+        ":create_bracket_include_headers_$this_target_name",
         ":modulemap_$this_target_name",
         ":umbrella_header_$this_target_name",
       ]
     }
 
+    action_foreach("create_bracket_include_headers_$this_target_name") {
+      script = "//tools_webrtc/apple/copy_framework_header.py"
+      sources = invoker.sources
+      output_name = invoker.output_name
+      outputs = [
+        "$target_gen_dir/$output_name.framework/WebRTC/{{source_file_part}}",
+      ]
+      args = [
+        "--input",
+        "{{source}}",
+        "--output",
+        rebase_path(target_gen_dir, root_build_dir) +
+            "/$output_name.framework/WebRTC/{{source_file_part}}",
+      ]
+    }
+
     bundle_data("copy_framework_headers_$this_target_name") {
-      forward_variables_from(invoker, [ "sources" ])
+      sources = get_target_outputs(
+              ":create_bracket_include_headers_$this_target_name")
 
       outputs = [ "{{bundle_contents_dir}}/Headers/{{source_file_part}}" ]
+      deps = [ ":create_bracket_include_headers_$this_target_name" ]
     }
 
     action("modulemap_$this_target_name") {
@@ -986,7 +1028,8 @@
     }
 
     action("umbrella_header_$this_target_name") {
-      forward_variables_from(invoker, [ "sources" ])
+      sources = get_target_outputs(
+              ":create_bracket_include_headers_$this_target_name")
 
       script = "//tools_webrtc/ios/generate_umbrella_header.py"
 
@@ -996,6 +1039,7 @@
                rebase_path(umbrella_header_path, root_build_dir),
                "--sources",
              ] + sources
+      deps = [ ":create_bracket_include_headers_$this_target_name" ]
     }
 
     bundle_data("copy_umbrella_header_$this_target_name") {