[blink] Fix some deps.

If a source file in a target #includes, transitively, a header
generated by e.g. a buildflag_header, mojom, or grit target, the
compiler may attempt to compile that translation unit before the
header is generated unless gn properly declares the dependency
on the action that generates the header.

This patch adds some missing deps that at least allows the
test_support target to be compiled from scratch without first
compiling some other target, which was blocking some builds in
the chromecast internal project.

Bug: 800764
Test: build the following target in a clean out directory:
      third_party/blink/renderer/modules/peerconnection:test_support

Change-Id: I1c469a37585f142df5c97e6a0ba21c76a889759f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1947558Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Simeon Anfinrud <sanfin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721767}

third_party/blink/renderer/platform/BUILD.gn

@@ -114,6 +114,7 @@ group("make_platform_generated") {
   visibility = []  # Allow re-assignment of list.
   visibility = [ "//third_party/blink/renderer/*" ]
   public_deps = [
+    ":bindings_buildflags",
     ":character_data",
     ":color_data",
     ":font_family_names",
@@ -141,7 +142,6 @@ group("blink_platform_public_deps") {
   visibility = []  # Allow re-assignment of list.
   visibility = [ "//third_party/blink/renderer/platform/*" ]
   public_deps = [
-    ":bindings_buildflags",
     ":make_platform_generated",
     "//base",
     "//cc",
@@ -1506,8 +1506,10 @@ jumbo_component("platform") {
     "//skia:skcms",
     "//third_party:freetype_harfbuzz",
     "//third_party/abseil-cpp/absl/types:optional",
+    "//third_party/blink/public:image_resources",
     "//third_party/blink/public/common",
     "//third_party/blink/public/mojom:embedded_frame_sink_mojo_bindings_blink",
+    "//third_party/blink/public/strings",
     "//third_party/ced",
     "//third_party/emoji-segmenter",
     "//third_party/icu",