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}

tools_webrtc/apple/copy_framework_header_test.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env python
+#  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+import unittest
+from copy_framework_header import replace_double_quote
+
+
+class TestCopyFramework(unittest.TestCase):
+    def testReplaceDoubleQuote(self):
+        self.assertEqual(replace_double_quote("""#import "RTCMacros.h\""""),
+                         """#import <WebRTC/RTCMacros.h>""")
+        self.assertEqual(replace_double_quote("""#import "RTCMacros.h\"\n"""),
+                         """#import <WebRTC/RTCMacros.h>\n""")
+        self.assertEqual(
+            replace_double_quote("""#import "UIDevice+RTCDevice.h\"\n"""),
+            """#import <WebRTC/UIDevice+RTCDevice.h>\n""")
+        self.assertEqual(
+            replace_double_quote("#import \"components/video_codec/" +
+                                 "RTCVideoDecoderFactoryH264.h\"\n"),
+            """#import <WebRTC/RTCVideoDecoderFactoryH264.h>\n""")
+        self.assertEqual(
+            replace_double_quote(
+                """@property(atomic, strong) RTC_OBJC_TYPE(RTCVideoFrame) *\n"""
+            ),
+            """@property(atomic, strong) RTC_OBJC_TYPE(RTCVideoFrame) *\n""")
+
+
+if __name__ == '__main__':
+    unittest.main()