DEPS clean up in the public/ directory

- Remove DEPS entries that are already inherited from the parent
- Move the media/midi/ entry to public/platform/modules/webmidi/
- Add a comment for the +platform entry to note that it's allowed only
  inside the INSIDE_BLINK preprocessor macro

Bug: 
Change-Id: Iad7811b4ee7ff0926c0f81a44975772266d9e80a
Reviewed-on: https://chromium-review.googlesource.com/593515
Commit-Queue: Takeshi Yoshino <tyoshino@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491320}

third_party/WebKit/public/README.md

@@ -2,7 +2,7 @@ Blink Public API
 ================
 
 This directory contains the public API for Blink. The API consists of a number
-of C++ header files, scripts, and GYP build files. We consider all other files
+of C++ header files, scripts, and GN build files. We consider all other files
 in Blink to be implementation details, which are subject to change at any time
 without notice.
 
@@ -47,7 +47,7 @@ The API does not use STL types, except for a small number of STL types that are
 used internally by Blink (e.g., std::pair). Instead, we use WTF containers to
 implement the API.
 
-The API uses some internal types (e.g., WebCore::Node). Typically, these types
+The API uses some internal types (e.g., blink::Node). Typically, these types
 are forward declared and are opaque to consumers of the API. In other cases,
 the full definitions are available behind the BLINK_IMPLEMENTATION
 preprocessor macro. In both cases, we continue to regard these internal types

third_party/WebKit/public/platform/DEPS

@@ -12,16 +12,8 @@ include_rules = [
     "+cc",
     "-cc/blink",
     "+components/viz/common",
-    "-core",
-    "-modules",
-    # TODO(toyoshim): Remove following media/midi direct dependency in public
-    # interface once Web MIDI starts calling the Mojo service inside Blink.
-    # http://crbug.com/582327
-    "+media/midi/midi_service.mojom-shared.h",
     "+mojo/public",
     "+net/http",
-    "+platform",
-    "+platform/weborigin",
     "+public/platform",
     "-public/web",
     "+services/service_manager/public/interfaces",
@@ -30,4 +22,7 @@ include_rules = [
     "+ui/gfx",
     "+url",
     "-web",
+
+    # Allowed only inside INSIDE_BLINK
+    "+platform",
 ]

third_party/WebKit/public/platform/modules/webmidi/DEPS

+include_rules = [
+    # TODO(toyoshim): Remove following media/midi direct dependency in public
+    # interface once Web MIDI starts calling the Mojo service inside Blink.
+    # http://crbug.com/582327
+    "+media/midi/midi_service.mojom-shared.h",
+]