Refactor: Make MediaCaptureDevicesDispatcher have pluggable handlers.

chrome/chrome_browser.gypi

Index: chrome/chrome_browser.gypi
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 7541dc43e12dc3a80062aaa0f8916ddc58bf6253..e6a1b3a497dd40375f8abf73d851ee4664448966 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -556,6 +556,7 @@
       'browser/media/desktop_media_picker.h',
       'browser/media/desktop_streams_registry.cc',
       'browser/media/desktop_streams_registry.h',
+      'browser/media/media_access_handler.h',
       'browser/media/media_capture_devices_dispatcher.cc',
       'browser/media/media_capture_devices_dispatcher.h',
       'browser/media/media_device_id_salt.cc',
@@ -578,6 +579,8 @@
       'browser/media/midi_permission_infobar_delegate.h',
       'browser/media/native_desktop_media_list.cc',
       'browser/media/native_desktop_media_list.h',
+      'browser/media/permission_bubble_media_access_handler.cc',
+      'browser/media/permission_bubble_media_access_handler.h',
       # TODO(brettw) should this go with the webrtc sources?
       'browser/media/webrtc_log_list.cc',
       'browser/media/webrtc_log_list.h',
@@ -1445,6 +1448,12 @@
       'browser/guest_view/web_view/context_menu_content_type_web_view.h',
       'browser/media/cast_transport_host_filter.cc',
       'browser/media/cast_transport_host_filter.h',
+      'browser/media/desktop_capture_access_handler.cc',
+      'browser/media/desktop_capture_access_handler.h',
+      'browser/media/extension_media_access_handler.cc',
+      'browser/media/extension_media_access_handler.h',
+      'browser/media/tab_capture_access_handler.cc',
+      'browser/media/tab_capture_access_handler.h',
       'browser/metrics/extensions_metrics_provider.cc',
       'browser/metrics/extensions_metrics_provider.h',
       'browser/renderer_context_menu/context_menu_content_type_app_mode.cc',