Add missing .h files to .gn files that have a .cc file next to it in the gn file already.

third_party/WebKit/Source/platform/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 import("//testing/test.gni")
 import("//third_party/WebKit/public/public_features.gni")
 import("//third_party/WebKit/Source/build/scripts/scripts.gni")
@@ skipping 1074 matching lines @@
     "mediastream/MediaStreamCenter.h",
     "mediastream/MediaStreamComponent.cpp",
     "mediastream/MediaStreamComponent.h",
     "mediastream/MediaStreamDescriptor.cpp",
     "mediastream/MediaStreamDescriptor.h",
     "mediastream/MediaStreamSource.cpp",
     "mediastream/MediaStreamSource.h",
     "mediastream/MediaStreamWebAudioSource.cpp",
     "mediastream/MediaStreamWebAudioSource.h",
     "mhtml/ArchiveResource.cpp",
+    "mhtml/ArchiveResource.h",
     "mhtml/MHTMLArchive.cpp",
     "mhtml/MHTMLArchive.h",
     "mhtml/MHTMLParser.cpp",
     "mhtml/MHTMLParser.h",
     "mojo/BluetoothStructTraits.cpp",
+    "mojo/BluetoothStructTraits.h",
     "mojo/CommonCustomTypesStructTraits.cpp",
+    "mojo/CommonCustomTypesStructTraits.h",
     "mojo/MojoHelper.h",
     "network/ContentSecurityPolicyParsers.cpp",
     "network/ContentSecurityPolicyParsers.h",
     "network/ContentSecurityPolicyResponseHeaders.cpp",
     "network/ContentSecurityPolicyResponseHeaders.h",
     "network/EncodedFormData.cpp",
     "network/EncodedFormData.h",
     "network/FormDataEncoder.cpp",
     "network/FormDataEncoder.h",
     "network/HTTPHeaderMap.cpp",
@@ skipping 436 matching lines @@
 }
 
 static_library("test_support") {
   visibility += [ "//third_party/WebKit/*" ]
   testonly = true
 
   sources = [
     "network/mime/MockMimeRegistry.h",
     "scheduler/base/task_queue_manager_delegate_for_test.cc",
     "scheduler/base/test_time_source.cc",
+    "scheduler/base/test_time_source.h",
     "scheduler/child/scheduler_tqm_delegate_for_test.cc",
+    "scheduler/child/scheduler_tqm_delegate_for_test.h",
     "scheduler/test/fake_renderer_scheduler.cc",
     "scheduler/test/fake_web_task_runner.cc",
     "scheduler/test/fake_web_task_runner.h",
     "scheduler/test/lazy_scheduler_message_loop_delegate_for_tests.cc",
     "scheduler/test/lazy_scheduler_message_loop_delegate_for_tests.h",
     "scheduler/test/renderer_scheduler_test_support.cc",
     "scroll/ScrollbarTestSuite.h",
     "testing/CompositorTest.cpp",
     "testing/CompositorTest.h",
     "testing/EmptyWebMediaPlayer.cpp",
@@ skipping 115 matching lines @@
     "fonts/android/FontCacheAndroidTest.cpp",
     "fonts/mac/FontFamilyMatcherMacTest.mm",
     "fonts/opentype/FontSettingsTest.cpp",
     "fonts/opentype/OpenTypeVerticalDataTest.cpp",
     "fonts/shaping/CachingWordShaperTest.cpp",
     "fonts/shaping/HarfBuzzShaperTest.cpp",
     "fonts/shaping/RunSegmenterTest.cpp",
     "geometry/DoubleRectTest.cpp",
     "geometry/FloatBoxTest.cpp",
     "geometry/FloatBoxTestHelpers.cpp",
+    "geometry/FloatBoxTestHelpers.h",
     "geometry/FloatPointTest.cpp",
     "geometry/FloatPolygonTest.cpp",
     "geometry/FloatQuadTest.cpp",
     "geometry/FloatRectTest.cpp",
     "geometry/FloatRoundedRectTest.cpp",
     "geometry/FloatSizeTest.cpp",
     "geometry/GeometryTestHelpers.cpp",
+    "geometry/GeometryTestHelpers.h",
     "geometry/IntRectTest.cpp",
     "geometry/LayoutRectOutsetsTest.cpp",
     "geometry/LayoutRectTest.cpp",
     "geometry/RegionTest.cpp",
     "graphics/BitmapImageTest.cpp",
     "graphics/CompositorMutableStateTest.cpp",
     "graphics/CompositorMutatorClientTest.cpp",
     "graphics/ContiguousContainerTest.cpp",
     "graphics/DeferredImageDecoderTestWoPlatform.cpp",
     "graphics/GraphicsContextTest.cpp",
@@ skipping 36 matching lines @@
     "network/HTTPParsersTest.cpp",
     "network/NetworkStateNotifierTest.cpp",
     "network/NetworkUtilsTest.cpp",
     "network/ParsedContentTypeTest.cpp",
     "network/mime/MIMETypeRegistryTest.cpp",
     "scheduler/base/intrusive_heap_unittest.cc",
     "scheduler/base/queueing_time_estimator_unittest.cc",
     "scheduler/base/task_queue_manager_unittest.cc",
     "scheduler/base/task_queue_selector_unittest.cc",
     "scheduler/base/test_count_uses_time_source.cc",
+    "scheduler/base/test_count_uses_time_source.h",
     "scheduler/base/thread_load_tracker_unittest.cc",
     "scheduler/base/time_domain_unittest.cc",
     "scheduler/base/work_queue_sets_unittest.cc",
     "scheduler/base/work_queue_unittest.cc",
     "scheduler/child/idle_canceled_delayed_task_sweeper_unittest.cc",
     "scheduler/child/idle_helper_unittest.cc",
     "scheduler/child/scheduler_helper_unittest.cc",
     "scheduler/child/scheduler_tqm_delegate_impl_unittest.cc",
     "scheduler/child/webthread_impl_for_worker_scheduler_unittest.cc",
     "scheduler/child/worker_scheduler_impl_unittest.cc",
@@ skipping 321 matching lines @@
     "//third_party/WebKit/Source:config",
     "//third_party/WebKit/Source:inside_blink",
   ]
 
   deps = [
     ":test_support",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }