Content "gn check" work.

Make content/gpu and content/plugin pass GN check. Significant work for most of content/test

Makes most of content/shell and content/test pass check. These are not all enabled yet pending a few remaining issues that are more difficult to solve.

The private content targets now allow content/test to include headers from them for non-component builds. Checking is disabled for content/test in component builds as described in the comment at the top of //content/BUILD.gn

Renames the ui/events/ipc according to GN style.

Annotates all content and gpu visibility declarations with why the're there, and fixes some incorrect ones that people added without understanding.

Reland of https://codereview.chromium.org/1828483002/ with significant changes.
TBR=jschuh (non-security-sensitive ipc build changes)

Review URL: https://codereview.chromium.org/1833193002

Cr-Commit-Position: refs/heads/master@{#383358}

33 files changed, 345 insertions, 53 deletions

diff --git a/.gn b/.gn
index f7ebb41..d851064 100644
--- a/.gn
+++ b/.gn
@@ -36,8 +36,21 @@ check_targets = [
   "//components/*",
 
   #"//content/*",  # A whole lot of errors.
+  "//content/gpu/*",
+  "//content/plugin/*",
   "//content/public/*",
   "//content/renderer/*",
+
+  #"//content/shell/*",  # Needs Android fix, bug 597020.
+
+  #"//content/test/*",  # A couple of errors left.
+  "//content/test:content_gl_benchmark",
+  "//content/test:content_gl_tests",
+  "//content/test:content_perftests",
+  "//content/test:content_site_isolation_browsertests",
+  "//content/test:content_test_mojo_bindings",
+  "//content/test:content_unittests",
+  "//content/test:test_support",
   "//courgette/*",
   "//crypto/*",
   "//data/*",
diff --git a/components/crash/content/app/BUILD.gn b/components/crash/content/app/BUILD.gn
index 87875e5..9638bea 100644
--- a/components/crash/content/app/BUILD.gn
+++ b/components/crash/content/app/BUILD.gn
@@ -45,13 +45,13 @@ source_set("app") {
 
   public_deps = [
     ":app_non_mac_win",
+    ":lib",
     "//third_party/kasko",
   ]
   deps = [
     "//base",
   ]
 
-  deps += [ ":lib" ]
   if (is_win) {
     deps += [
       # TODO(fdoray): Remove this once the PreRead field trial has expired.
diff --git a/content/BUILD.gn b/content/BUILD.gn
index 1d32ad2..1ece4f9 100644
--- a/content/BUILD.gn
+++ b/content/BUILD.gn
@@ -37,6 +37,23 @@ config("content_implementation") {
 # //content/public/browser and similar targets to avoid double-linking (these
 # targets make sure the dependency goes through the content shared library
 # when doing a component build).
+#
+# TESTS
+# -----
+# Tests are a challenge. The content tests need to access internals of
+# content/browser, for example, but the tests themselves are outside of the
+# content component (which is a shared library in the component build). To
+# prevent external-to-content targets from depending on private headers,
+# the non-public content/browser target is not a public dep of the content
+# component. But this means there is also no public path for the content
+# tests and no way to restrict that just to //content/test/* if we added one.
+#
+# As a result, we check deps for //content/test/* only in non-component builds
+# (which should verify the dependencies are correct for both component and
+# non-component cases equally). There are targets like
+# //content/browser:for_content_tests that allow content/test to depend on the
+# //content/browser target only in non-component builds (when there are no
+# linking problems) for when check is enabled.
 
 if (!is_nacl_nonsfi) {
   content_shared_components = [
@@ -99,6 +116,7 @@ grit("resources") {
 # This target exists to "hold" the content_export header so we can do proper
 # inclusion testing of it.
 source_set("export") {
+  # Must only be used inside of content.
   visibility = [ "//content/*" ]
   sources = [
     "common/content_export.h",
diff --git a/content/app/BUILD.gn b/content/app/BUILD.gn
index abe8a75..1491439 100644
--- a/content/app/BUILD.gn
+++ b/content/app/BUILD.gn
@@ -67,13 +67,26 @@ if (!is_multi_dll_chrome) {
 source_set("both") {
   # Only the public target should depend on this. All other targets (even
   # internal content ones) should depend on the public one.
-  visibility = [ "//content/public/app:*" ]
+  visibility = [
+    ":both_for_content_tests",  # See top of //content/BUILD.gn for why.
+    "//content/public/app:*",
+  ]
 
   sources = content_app_sources
   configs += content_app_extra_configs
   deps = content_app_deps
 }
 
+# See comment at the top of //content/BUILD.gn for how this works.
+group("both_for_content_tests") {
+  visibility = [ "//content/test/*" ]
+  if (!is_component_build) {
+    public_deps = [
+      ":both",
+    ]
+  }
+}
+
 if (is_multi_dll_chrome) {
   # It doesn't make sense to do the browser/child dll split in component mode.
   assert(!is_component_build)
diff --git a/content/browser/BUILD.gn b/content/browser/BUILD.gn
index 9245309..fb8d3a9 100644
--- a/content/browser/BUILD.gn
+++ b/content/browser/BUILD.gn
@@ -11,7 +11,10 @@ import("//mojo/public/mojo_application_manifest.gni")
 source_set("browser") {
   # Only the public target should depend on this. All other targets (even
   # internal content ones) should depend on the public one.
-  visibility = [ "//content/public/browser:browser_sources" ]
+  visibility = [
+    ":for_content_tests",  # See top of //content/BUILD.gn for why.
+    "//content/public/browser:browser_sources",
+  ]
 
   configs += [
     "//build/config:precompiled_headers",
@@ -48,7 +51,7 @@ source_set("browser") {
     "//content/browser/notifications:notification_proto",
     "//content/browser/service_worker:service_worker_proto",
     "//content/browser/speech/proto",
-    "//content/common:mojo_bindings",
+    "//content/common",
     "//content/public/common:common_sources",
     "//content/public/common:mojo_bindings",
     "//crypto",
@@ -526,6 +529,16 @@ source_set("browser") {
   }
 }
 
+# See comment at the top of //content/BUILD.gn for how this works.
+group("for_content_tests") {
+  visibility = [ "//content/test/*" ]
+  if (!is_component_build) {
+    public_deps = [
+      ":browser",
+    ]
+  }
+}
+
 mojo_application_manifest("chrome_manifest") {
   type = "exe"
   application_name = "chrome"
diff --git a/content/browser/tracing/BUILD.gn b/content/browser/tracing/BUILD.gn
index 2122c79..b71bf1b 100644
--- a/content/browser/tracing/BUILD.gn
+++ b/content/browser/tracing/BUILD.gn
@@ -12,7 +12,7 @@ tracing_gen_dir = "$root_gen_dir/content/browser/tracing"
 tracing_grd = "$tracing_gen_dir/tracing_resources.grd"
 
 action("generate_tracing_grd") {
-  visibility = [ ":*" ]
+  visibility = [ ":*" ]  # Depend on ":resources" to get this.
   script = "generate_trace_viewer_grd.py"
 
   input_pages = [
diff --git a/content/child/BUILD.gn b/content/child/BUILD.gn
index ee79f18..910ba0e 100644
--- a/content/child/BUILD.gn
+++ b/content/child/BUILD.gn
@@ -7,9 +7,18 @@ import("//build/config/ui.gni")
 import("//content/child/child.gni")
 
 source_set("child") {
-  # Only the public target should depend on this. All other targets (even
-  # internal content ones) should depend on the public one.
-  visibility = [ "//content/public/child:child_sources" ]
+  # Targets external to content should always link to the public API.
+  # Internal targets can link to this but only if they're child processes
+  # (i.e. not content/browser or content/common) and only if they're inside the
+  # content component (i.e. not content/test or content/shell).
+  visibility = [
+    "//content/gpu/*",
+    "//content/plugin/*",
+    "//content/ppapi_plugin/*",
+    "//content/public/child:child_sources",
+    "//content/renderer/*",
+    "//content/utility/*",
+  ]
 
   sources = rebase_path(content_child_gypi_values.private_child_sources,
                         ".",
@@ -33,7 +42,7 @@ source_set("child") {
     "//components/webcrypto",
     "//content/app/resources",
     "//content/app/strings",
-    "//content/common:mojo_bindings",
+    "//content/common",
     "//crypto:platform",
     "//mojo/common",
     "//mojo/message_pump",
diff --git a/content/common/BUILD.gn b/content/common/BUILD.gn
index 36c5057..9a0ed5d 100644
--- a/content/common/BUILD.gn
+++ b/content/common/BUILD.gn
@@ -126,9 +126,11 @@ if (is_mac) {
 }
 
 source_set("common") {
-  # Only the public target should depend on this. All other targets (even
-  # internal content ones) should depend on the public one.
-  visibility = [ "//content/public/common:common_sources" ]
+  # Targets external to content should always link to the public API.
+  # In addition, targets outside of the content component (shell and tests)
+  # must not link to this because it will duplicate the code in the component
+  # build.
+  visibility = [ "//content/*" ]
 
   sources = rebase_path(content_common_gypi_values.private_common_sources,
                         ".",
@@ -195,7 +197,7 @@ source_set("common") {
     "//ui/accessibility",
     "//ui/base",
     "//ui/base/ime",
-    "//ui/events/ipc:events_ipc",
+    "//ui/events/ipc",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/gfx/ipc",
@@ -519,7 +521,23 @@ source_set("common") {
   }
 }
 
+# See comment at the top of //content/BUILD.gn for how this works.
+group("for_content_tests") {
+  visibility = [ "//content/test/*" ]
+  if (!is_component_build) {
+    public_deps = [
+      ":common",
+    ]
+  }
+}
+
 mojom("mojo_bindings") {
+  # This interface is internal to content. However, this is not exported from
+  # the content component shared library. Code in content but outside of the
+  # content component (content/test or content/shell) should link to this
+  # directly.
+  visibility = [ "//content/*" ]
+
   sources = [
     "application_setup.mojom",
     "background_sync_service.mojom",
diff --git a/content/gpu/BUILD.gn b/content/gpu/BUILD.gn
index 7736a55..a31e94f 100644
--- a/content/gpu/BUILD.gn
+++ b/content/gpu/BUILD.gn
@@ -8,7 +8,7 @@ import("//media/media_options.gni")
 
 # See //content/BUILD.gn for how this works.
 group("gpu") {
-  visibility = [ "//content/*" ]
+  visibility = [ "//content/*" ]  # This is an internal content API.
 
   if (is_component_build) {
     public_deps = [
@@ -22,6 +22,8 @@ group("gpu") {
 }
 
 source_set("gpu_sources") {
+  # This is an internal content API. Code outside of the content "component"
+  # (like content/test and content/shell) should depend on ":gpu" above.
   visibility = [ "//content/*" ]
 
   sources = [
@@ -42,21 +44,23 @@ source_set("gpu_sources") {
 
   deps = [
     "//base",
+    "//base/third_party/dynamic_annotations",
+    "//components/tracing",
     "//content:export",
+    "//content/common",
     "//content/public/child:child_sources",
     "//content/public/common:common_sources",
     "//gpu:gpu",
     "//gpu/ipc/common:command_buffer_traits",
     "//ipc",
+    "//media/mojo/services:application_factory",
     "//mojo/shell/public/interfaces",
     "//skia",
+    "//ui/events/ipc",
+    "//ui/gfx/ipc",
     "//ui/gl",
   ]
 
-  public_deps = [
-    "//content/common:mojo_bindings",
-  ]
-
   if (mojo_media_host == "gpu") {
     deps += [ "//media/mojo/services:application_factory" ]
   }
@@ -68,6 +72,7 @@ source_set("gpu_sources") {
     ]
     libs = [ "setupapi.lib" ]
     deps += [
+      "//sandbox",
       "//third_party/angle:libEGL",
       "//third_party/angle:libGLESv2",
     ]
@@ -81,6 +86,10 @@ source_set("gpu_sources") {
     deps += [ "//ui/events/platform/x11" ]
   }
 
+  if (use_ozone) {
+    deps += [ "//ui/ozone" ]
+  }
+
   if (enable_vulkan) {
     deps += [ "//gpu/vulkan" ]
   }
diff --git a/content/plugin/BUILD.gn b/content/plugin/BUILD.gn
index 6e87a12..94dc6d8 100644
--- a/content/plugin/BUILD.gn
+++ b/content/plugin/BUILD.gn
@@ -32,12 +32,19 @@ if (enable_plugins && !is_linux) {
 
     deps = [
       "//content:export",
+      "//content/child",
       "//content/public/common:common_sources",
       "//mojo/shell/public/interfaces",
       "//skia",
       "//third_party/WebKit/public:blink",
       "//third_party/npapi",
+      "//ui/gfx",
+      "//ui/surface",
     ]
+
+    if (is_win) {
+      deps += [ "//sandbox" ]
+    }
   }
 } else {
   # This way it can be unconditionally depended on.
diff --git a/content/ppapi_plugin/BUILD.gn b/content/ppapi_plugin/BUILD.gn
index e127a3d..eb608e7 100644
--- a/content/ppapi_plugin/BUILD.gn
+++ b/content/ppapi_plugin/BUILD.gn
@@ -3,7 +3,7 @@
 # found in the LICENSE file.
 
 group("ppapi_plugin") {
-  visibility = [ "//content/*" ]
+  visibility = [ "//content/*" ]  # This is an internal content API.
 
   if (is_component_build) {
     public_deps = [
@@ -17,7 +17,11 @@ group("ppapi_plugin") {
 }
 
 source_set("ppapi_plugin_sources") {
-  visibility = [ "//content/*" ]
+  # Depend on via ":ppapi_plugin above.
+  visibility = [
+    ":ppapi_plugin",
+    "//content",  # For the component build.
+  ]
 
   sources = [
     "broker_process_dispatcher.cc",
diff --git a/content/public/browser/BUILD.gn b/content/public/browser/BUILD.gn
index 643cb8f..5b04b1e 100644
--- a/content/public/browser/BUILD.gn
+++ b/content/public/browser/BUILD.gn
@@ -19,6 +19,7 @@ group("browser") {
 }
 
 source_set("browser_sources") {
+  # External code should depend on via ":browser" above.
   visibility = [ "//content/*" ]
 
   sources = rebase_path(content_browser_gypi_values.public_browser_sources,
@@ -40,7 +41,7 @@ source_set("browser_sources") {
   ]
   deps = [
     "//cc",
-    "//content/browser",
+    "//content/browser",  # Must not be public_deps!
     "//content/public/common:common_sources",
     "//gpu",
     "//media",
diff --git a/content/public/child/BUILD.gn b/content/public/child/BUILD.gn
index 6573af8..68c9986 100644
--- a/content/public/child/BUILD.gn
+++ b/content/public/child/BUILD.gn
@@ -24,6 +24,7 @@ group("child") {
 }
 
 source_set("child_sources") {
+  # External code should depend in via ":child" above.
   visibility = [ "//content/*" ]
 
   sources = rebase_path(content_child_gypi_values.public_child_sources,
diff --git a/content/public/common/BUILD.gn b/content/public/common/BUILD.gn
index 39a95fd..02712fe 100644
--- a/content/public/common/BUILD.gn
+++ b/content/public/common/BUILD.gn
@@ -78,6 +78,7 @@ source_set("static_switches") {
 }
 
 source_set("common_sources") {
+  # External code should depend on via ":common" above.
   visibility = [ "//content/*" ]
 
   sources = rebase_path(content_common_gypi_values.public_common_sources,
diff --git a/content/public/gpu/BUILD.gn b/content/public/gpu/BUILD.gn
index 63550aa..fa0be53 100644
--- a/content/public/gpu/BUILD.gn
+++ b/content/public/gpu/BUILD.gn
@@ -16,6 +16,8 @@ group("gpu") {
 }
 
 source_set("gpu_sources") {
+  # You must depend on this via //content/public/gpu above for the component
+  # build to work properly.
   visibility = [ "//content/*" ]
 
   configs += [ "//content:content_implementation" ]
@@ -30,4 +32,6 @@ source_set("gpu_sources") {
     "//content/gpu:gpu_sources",
     "//content/public/common:common_sources",
   ]
+
+  allow_circular_includes_from = [ "//content/gpu:gpu_sources" ]
 }
diff --git a/content/public/plugin/BUILD.gn b/content/public/plugin/BUILD.gn
index e4c4d36..1693b4e 100644
--- a/content/public/plugin/BUILD.gn
+++ b/content/public/plugin/BUILD.gn
@@ -16,6 +16,7 @@ group("plugin") {
 }
 
 source_set("plugin_sources") {
+  # External code should depend on via ":plugin" above.
   visibility = [ "//content/*" ]
 
   sources = [
@@ -24,7 +25,13 @@ source_set("plugin_sources") {
 
   deps = [
     "//base",
-    "//content/plugin",
+    "//content/plugin",  # Must not be a public dep.
     "//content/public/common:common_sources",
   ]
+
+  allow_circular_includes_from = [
+    # This target is a pair with content/plugin. They always go together and
+    # include headers from each other.
+    "//content/plugin",
+  ]
 }
diff --git a/content/public/renderer/BUILD.gn b/content/public/renderer/BUILD.gn
index c31a7bb..c0eaab1 100644
--- a/content/public/renderer/BUILD.gn
+++ b/content/public/renderer/BUILD.gn
@@ -19,6 +19,7 @@ group("renderer") {
 }
 
 source_set("renderer_sources") {
+  # External code should depend on via ":renderer" above.
   visibility = [ "//content/*" ]
 
   sources = rebase_path(content_renderer_gypi_values.public_renderer_sources,
diff --git a/content/public/utility/BUILD.gn b/content/public/utility/BUILD.gn
index c9fce03..c0e514c 100644
--- a/content/public/utility/BUILD.gn
+++ b/content/public/utility/BUILD.gn
@@ -18,6 +18,7 @@ group("utility") {
 }
 
 source_set("utility_sources") {
+  # External code should depend on via ":utility" above.
   visibility = [ "//content/*" ]
 
   sources = rebase_path(content_utility_gypi_values.public_utility_sources,
diff --git a/content/renderer/BUILD.gn b/content/renderer/BUILD.gn
index bf45546..f9a554d0 100644
--- a/content/renderer/BUILD.gn
+++ b/content/renderer/BUILD.gn
@@ -10,7 +10,10 @@ import("//media/media_options.gni")
 source_set("renderer") {
   # Only the public target should depend on this. All other targets (even
   # internal content ones) should depend on the public one.
-  visibility = [ "//content/public/renderer:renderer_sources" ]
+  visibility = [
+    ":for_content_tests",
+    "//content/public/renderer:renderer_sources",
+  ]
 
   sources = rebase_path(content_renderer_gypi_values.private_renderer_sources,
                         ".",
@@ -23,6 +26,7 @@ source_set("renderer") {
   ]
   defines = []
 
+  public_deps = []
   deps = [
     "//base:i18n",
     "//cc",
@@ -33,7 +37,7 @@ source_set("renderer") {
     "//components/scheduler:scheduler",
     "//components/url_formatter",
     "//content:resources",
-    "//content/common:mojo_bindings",
+    "//content/common",
     "//content/gpu:gpu_sources",
     "//content/public/child:child_sources",
     "//content/public/common:common_sources",
@@ -87,7 +91,7 @@ source_set("renderer") {
   allow_circular_includes_from = []
 
   if (use_aura) {
-    deps += [ "//content/renderer/mus" ]
+    public_deps += [ "//content/renderer/mus" ]
     allow_circular_includes_from += [ "//content/renderer/mus" ]
   }
 
@@ -247,3 +251,13 @@ source_set("renderer") {
     deps += [ "//ui/ozone" ]
   }
 }
+
+# See comment at the top of //content/BUILD.gn for how this works.
+group("for_content_tests") {
+  visibility = [ "//content/test/*" ]
+  if (!is_component_build) {
+    public_deps = [
+      ":renderer",
+    ]
+  }
+}
diff --git a/content/renderer/mus/BUILD.gn b/content/renderer/mus/BUILD.gn
index dc471fc..6155680 100644
--- a/content/renderer/mus/BUILD.gn
+++ b/content/renderer/mus/BUILD.gn
@@ -3,6 +3,9 @@
 # found in the LICENSE file.
 
 source_set("mus") {
+  # Depend on this only via //content/renderer.
+  visibility = [ "//content/renderer/*" ]
+
   sources = [
     "compositor_mus_connection.cc",
     "compositor_mus_connection.h",
@@ -19,7 +22,7 @@ source_set("mus") {
     "//cc",
     "//components/mus/public/cpp",
     "//components/mus/public/interfaces",
-    "//content/common:mojo_bindings",
+    "//content/common",
     "//content/public/common:common_sources",
     "//mojo/common",
     "//mojo/converters/blink",
diff --git a/content/shell/BUILD.gn b/content/shell/BUILD.gn
index 6ce50f8..4fd4c91 100644
--- a/content/shell/BUILD.gn
+++ b/content/shell/BUILD.gn
@@ -221,12 +221,14 @@ static_library("content_shell_lib") {
     "//content/app/strings",
     "//content/gpu",
     "//content/test:layouttest_support",
+    "//content/test:test_support",
     "//device/bluetooth",
     "//device/bluetooth:mocks",
     "//gin",
     "//gpu",
     "//ipc",
     "//media",
+    "//media/mojo/services:application_factory",
     "//net",
     "//net:net_resources",
     "//skia",
@@ -255,6 +257,7 @@ static_library("content_shell_lib") {
       "//content/ppapi_plugin",
       "//ppapi:blink_deprecated_test_plugin",
       "//ppapi:blink_test_plugin",
+      "//ppapi/shared_impl",
     ]
   }
   if (mojo_media_host == "browser") {
@@ -270,7 +273,10 @@ static_library("content_shell_lib") {
   }
 
   if (is_linux) {
-    deps += [ "//build/linux:fontconfig" ]
+    deps += [
+      "//build/linux:fontconfig",
+      "//ui/gfx:test_support",
+    ]
   }
 
   if (use_x11) {
@@ -289,7 +295,10 @@ static_library("content_shell_lib") {
   }
 
   if (is_posix && !is_mac) {
-    deps += [ "//components/crash/content/browser" ]
+    deps += [
+      "//components/crash/content/app",
+      "//components/crash/content/browser",
+    ]
   }
 
   if (use_aura) {
@@ -308,6 +317,7 @@ static_library("content_shell_lib") {
         "//ui/views",
         "//ui/views:test_support",
         "//ui/views/controls/webview",
+        "//ui/wm:test_support",
       ]
     } else {
       sources += [ "browser/shell_aura.cc" ]
@@ -344,6 +354,7 @@ static_library("content_shell_lib") {
 }
 
 grit("content_shell_resources_grit") {
+  # External code should depend on ":resources" instead.
   visibility = [ ":*" ]
   source = "shell_resources.grd"
   outputs = [
diff --git a/content/test/BUILD.gn b/content/test/BUILD.gn
index acb1539..8c5b725 100644
--- a/content/test/BUILD.gn
+++ b/content/test/BUILD.gn
@@ -24,6 +24,12 @@ content_tests_gypi_values =
 source_set("test_support") {
   testonly = true
 
+  # See comment at the top of //content/BUILD.gn for why this is disabled in
+  # component builds.
+  if (is_component_build) {
+    check_includes = false
+  }
+
   configs += [
     "//build/config:precompiled_headers",
     "//v8:external_startup_data",
@@ -36,19 +42,26 @@ source_set("test_support") {
     "//third_party/WebKit/public:blink",
   ]
   deps = [
+    ":browsertest_base",
     ":content_test_mojo_bindings",
+    "//base/third_party/dynamic_annotations",
     "//cc",
     "//cc:test_support",
     "//cc/blink",
+    "//cc/surfaces",
     "//components/scheduler:scheduler",
     "//components/scheduler:test_support",
+    "//content/app:both_for_content_tests",
     "//content/browser/speech/proto",
     "//content/gpu",
+    "//content/public/browser",
     "//content/public/child",
     "//content/public/plugin",
     "//content/public/renderer",
     "//content/public/utility",
+    "//content/renderer:for_content_tests",
     "//content/shell:pak",
+    "//content/utility:for_content_tests",
     "//ipc:test_support",
     "//ipc/mojo",
     "//media",
@@ -120,6 +133,7 @@ source_set("test_support") {
     deps += [
       "//third_party/libjingle:libjingle_webrtc",
       "//third_party/libjingle:libpeerconnection",
+      "//third_party/webrtc/base:rtc_base",
       "//third_party/webrtc/modules/video_capture",
     ]
   }
@@ -180,6 +194,12 @@ source_set("test_support") {
 source_set("browsertest_support") {
   testonly = true
 
+  # See comment at the top of //content/BUILD.gn for why this is disabled in
+  # component builds.
+  if (is_component_build) {
+    check_includes = false
+  }
+
   sources = [
     "../public/test/content_browser_test.cc",
     "../public/test/content_browser_test.h",
@@ -192,10 +212,24 @@ source_set("browsertest_support") {
   ]
 
   deps = [
+    ":browsertest_base",
+    ":test_support",
+    "//base",
+    "//base:i18n",
+    "//base/test:test_config",
+    "//base/test:test_support",
+    "//cc/surfaces",
+    "//content/app:both_for_content_tests",
+    "//content/browser:for_content_tests",
     "//content/shell:content_shell_lib",
+    "//gin",
+    "//media",
+    "//net",
     "//skia",
     "//testing/gtest",
     "//ui/accessibility:ax_gen",
+    "//ui/base",
+    "//ui/base/ime",
   ]
 
   if (is_android) {
@@ -220,12 +254,14 @@ source_set("browsertest_base") {
   ]
 
   public_deps = [
+    "//content/browser:for_content_tests",
     "//content/public/browser",
     "//content/public/common",
     "//third_party/WebKit/public:blink",
   ]
   deps = [
     "//base:base",
+    "//content/public/app:both",
     "//net:test_support",
     "//testing/gtest",
     "//ui/base",
@@ -253,6 +289,13 @@ mojom("web_ui_test_mojo_bindings") {
 # GYP version //content/content_tests.gypi:layouttest_support_content
 static_library("layouttest_support") {
   testonly = true
+
+  # See comment at the top of //content/BUILD.gn for why this is disabled in
+  # component builds.
+  if (is_component_build) {
+    check_includes = false
+  }
+
   sources =
       rebase_path(content_tests_gypi_values.layouttest_support_content_sources,
                   ".",
@@ -263,7 +306,11 @@ static_library("layouttest_support") {
     "//cc",
     "//cc/blink",
     "//components/test_runner:test_runner",
+    "//content/browser:for_content_tests",
     "//content/public/common",
+
+    #"//content/shell:content_shell_lib",
+    "//content/renderer:for_content_tests",
     "//mojo/edk/test:test_support",
     "//skia",
     "//ui/accessibility:ax_gen",
@@ -339,6 +386,12 @@ group("content_site_isolation_browsertests") {
 }
 
 test("content_browsertests") {
+  # See comment at the top of //content/BUILD.gn for why this is disabled in
+  # component builds.
+  if (is_component_build) {
+    check_includes = false
+  }
+
   sources = rebase_path(content_tests_gypi_values.content_browsertests_sources,
                         ".",
                         "//content")
@@ -389,15 +442,22 @@ test("content_browsertests") {
   deps = [
     ":browsertest_base",
     ":browsertest_support",
+    ":content_test_mojo_bindings",
     ":web_ui_test_mojo_bindings",
     "//base/test:test_support",
+    "//components/scheduler",
     "//content:resources",
+    "//content/app:both_for_content_tests",
+    "//content/browser:for_content_tests",
     "//content/browser/background_sync:background_sync_proto",
     "//content/common:mojo_bindings",
     "//content/gpu",
+    "//content/public/browser",
+    "//content/public/child",
     "//content/public/common",
     "//content/public/plugin",
     "//content/public/renderer",
+    "//content/renderer:for_content_tests",
     "//content/shell:content_shell_lib",
     "//content/shell:pak",
     "//content/test:test_support",
@@ -406,9 +466,9 @@ test("content_browsertests") {
     "//device/vibration:mojo_bindings",
     "//gin",
     "//gpu",
+    "//gpu/blink",
     "//ipc:test_support",
-    "//media:media_features",
-    "//media:shared_memory_support",
+    "//media",
     "//media:test_support",
     "//media/audio:test_support",
     "//media/base:test_support",
@@ -419,6 +479,7 @@ test("content_browsertests") {
     "//mojo/shell/public/cpp:cpp_for_chromium",
     "//mojo/test:test_support",
     "//net:test_support",
+    "//storage/browser",
     "//testing/gmock",
     "//testing/gtest",
     "//third_party/WebKit/public:blink",
@@ -427,8 +488,9 @@ test("content_browsertests") {
     "//third_party/zlib",
     "//ui/accessibility",
     "//ui/accessibility:ax_gen",
-    "//ui/base",
+    "//ui/base:test_support",
     "//ui/base/ime",
+    "//ui/compositor",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/gl",
@@ -447,7 +509,7 @@ test("content_browsertests") {
       "//ppapi/host",
       "//ppapi/proxy",
       "//ppapi/proxy:ipc",
-      "//ppapi/shared_impl",
+      "//ppapi/shared_impl:test_support",
     ]
     data_deps += [ "//ppapi:ppapi_tests" ]
   }
@@ -524,6 +586,7 @@ test("content_browsertests") {
             content_tests_gypi_values.content_browsertests_plugins_sources,
             ".",
             "//content")
+    deps += [ "//ppapi/proxy:test_support" ]
     data_deps += [ "//ppapi:ppapi_tests" ]
   }
 
@@ -543,6 +606,7 @@ test("content_browsertests") {
 
   if (use_aura) {
     deps += [
+      "//ui/aura",
       "//ui/touch_selection:test_support",
       "//ui/touch_selection:touch_selection",
     ]
@@ -556,6 +620,12 @@ test("content_browsertests") {
 }
 
 test("content_unittests") {
+  # See comment at the top of //content/BUILD.gn for why this is disabled in
+  # component builds.
+  if (is_component_build) {
+    check_includes = false
+  }
+
   defines = []
   sources = rebase_path(content_tests_gypi_values.content_unittests_sources,
                         ".",
@@ -573,14 +643,17 @@ test("content_unittests") {
   configs += [ "//build/config:precompiled_headers" ]
 
   deps = [
+    ":content_test_mojo_bindings",
     ":test_support",
     "//base/test:test_support",
     "//base/third_party/dynamic_annotations",
     "//cc",
     "//cc:test_support",
     "//cc/surfaces",
+    "//components/scheduler",
     "//content:resources",
-    "//content/browser/background_sync:background_sync_proto",
+    "//content/app:both_for_content_tests",
+    "//content/browser:for_content_tests",
     "//content/browser/cache_storage:cache_storage_proto",
     "//content/browser/notifications:notification_proto",
     "//content/browser/service_worker:service_worker_proto",
@@ -593,6 +666,7 @@ test("content_unittests") {
     "//content/public/common:mojo_bindings",
     "//content/public/plugin",
     "//content/public/renderer",
+    "//content/renderer:for_content_tests",
     "//crypto",
     "//device/battery",
     "//device/battery:mojo_bindings",
@@ -610,6 +684,8 @@ test("content_unittests") {
     "//mojo/public/cpp/bindings",
     "//net:extras",
     "//net:test_support",
+    "//ppapi/c",
+    "//printing",
     "//skia",
     "//sql",
     "//sql:test_support",
@@ -622,11 +698,12 @@ test("content_unittests") {
     "//third_party/leveldatabase",
     "//third_party/libjingle",
     "//third_party/re2",
+    "//third_party/widevine/cdm:version_h",
     "//ui/accessibility",
-    "//ui/base",
+    "//ui/base:test_support",
     "//ui/compositor:test_support",
     "//ui/events/blink",
-    "//ui/gfx",
+    "//ui/gfx:test_support",
     "//ui/gfx/geometry",
     "//ui/gfx/ipc",
     "//ui/gl",
@@ -646,6 +723,11 @@ test("content_unittests") {
         rebase_path(content_tests_gypi_values.content_unittests_plugins_sources,
                     ".",
                     "//content")
+    deps += [
+      "//ppapi/host",
+      "//ppapi/proxy:test_support",
+      "//ppapi/shared_impl:test_support",
+    ]
   }
 
   if (enable_webrtc) {
@@ -656,6 +738,8 @@ test("content_unittests") {
     deps += [
       "//third_party/libjingle:libjingle_webrtc",
       "//third_party/libjingle:libpeerconnection",
+      "//third_party/webrtc/base:rtc_base",
+      "//third_party/webrtc/modules/desktop_capture:primitives",
       "//third_party/webrtc/modules/video_capture",
       "//ui/shell_dialogs:shell_dialogs",
     ]
@@ -703,7 +787,10 @@ test("content_unittests") {
     # Search for comments about "xcode_settings" in chrome_tests.gypi.
     ldflags = [ "-Wl,-ObjC" ]
 
-    deps += [ "//third_party/ocmock" ]
+    deps += [
+      "//third_party/mozilla",
+      "//third_party/ocmock",
+    ]
   }
   if (is_chromeos) {
     sources -= [ "../browser/geolocation/wifi_data_provider_linux_unittest.cc" ]
@@ -738,7 +825,7 @@ test("content_unittests") {
   if (use_aura) {
     deps += [
       "//components/mus/public/cpp/tests:unittest_support",
-      "//ui/aura",
+      "//ui/aura:test_support",
       "//ui/aura_extra",
       "//ui/wm",
     ]
@@ -783,9 +870,19 @@ test("content_unittests") {
   if (is_mac && use_openssl) {
     deps += [ "//third_party/boringssl" ]
   }
+
+  if (use_x11) {
+    deps += [ "//ui/gfx/x" ]
+  }
 }
 
 test("content_perftests") {
+  # See comment at the top of //content/BUILD.gn for why this is disabled in
+  # component builds.
+  if (is_component_build) {
+    check_includes = false
+  }
+
   sources = [
     "../browser/renderer_host/input/input_router_impl_perftest.cc",
     "../common/cc_messages_perftest.cc",
@@ -794,6 +891,7 @@ test("content_perftests") {
   deps = [
     "//base/test:test_support",
     "//cc",
+    "//content/browser:for_content_tests",
     "//content/public/browser",
     "//content/public/common",
     "//content/test:test_support",
@@ -810,6 +908,12 @@ test("content_perftests") {
 }
 
 test("content_gl_tests") {
+  # See comment at the top of //content/BUILD.gn for why this is disabled in
+  # component builds.
+  if (is_component_build) {
+    check_includes = false
+  }
+
   sources = [
     "../browser/compositor/gl_helper_unittest.cc",
     "../common/gpu/client/gpu_in_process_context_tests.cc",
@@ -819,9 +923,13 @@ test("content_gl_tests") {
   deps = [
     ":test_support",
     "//base/test:test_support",
+    "//content/browser:for_content_tests",
     "//content/public/common",
     "//gpu/blink",
+    "//gpu/command_buffer/client:gl_in_process_context",
+    "//gpu/command_buffer/client:gles2_implementation",
     "//gpu/command_buffer/common",
+    "//media",
     "//testing/gtest",
     "//third_party/WebKit/public:blink",
     "//ui/base",
@@ -847,6 +955,12 @@ test("content_gl_tests") {
 }
 
 test("content_gl_benchmark") {
+  # See comment at the top of //content/BUILD.gn for why this is disabled in
+  # component builds.
+  if (is_component_build) {
+    check_includes = false
+  }
+
   sources = [
     "../browser/compositor/gl_helper_benchmark.cc",
     "run_gl_benchmark.cc",
@@ -855,8 +969,11 @@ test("content_gl_benchmark") {
   deps = [
     ":test_support",
     "//base/test:test_support",
+    "//content/browser:for_content_tests",
     "//content/public/common",
     "//gpu/blink",
+    "//gpu/command_buffer/client:gl_in_process_context",
+    "//gpu/command_buffer/client:gles2_implementation",
     "//testing/gtest",
     "//third_party/WebKit/public:blink",
     "//ui/base",
diff --git a/content/utility/BUILD.gn b/content/utility/BUILD.gn
index 9aea9db..0ef4261 100644
--- a/content/utility/BUILD.gn
+++ b/content/utility/BUILD.gn
@@ -7,8 +7,11 @@ import("//media/media_options.gni")
 
 source_set("utility") {
   # Only the public target should depend on this. All other targets (even
-  # internal content ones) should depend on the public one.
-  visibility = [ "//content/public/utility:utility_sources" ]
+  # internal content ones other than test) should depend on the public one.
+  visibility = [
+    ":for_content_tests",
+    "//content/public/utility:utility_sources",
+  ]
 
   sources =
       rebase_path(content_utility_gypi_values.utility_sources, ".", "//content")
@@ -17,11 +20,13 @@ source_set("utility") {
 
   deps = [
     "//base",
+    "//components/scheduler",
     "//content:export",
     "//content/public/child:child_sources",
     "//content/public/common:common_sources",
     "//content/public/common:mojo_bindings",
     "//courgette:courgette_lib",
+    "//media/mojo/services:application_factory",
     "//mojo/common",
     "//mojo/public/cpp/bindings",
     "//mojo/shell",
@@ -35,3 +40,13 @@ source_set("utility") {
     deps += [ "//media/mojo/services:application_factory" ]
   }
 }
+
+# See comment at the top of //content/BUILD.gn for how this works.
+group("for_content_tests") {
+  visibility = [ "//content/test/*" ]
+  if (!is_component_build) {
+    public_deps = [
+      ":utility",
+    ]
+  }
+}
diff --git a/gpu/command_buffer/client/BUILD.gn b/gpu/command_buffer/client/BUILD.gn
index fb623e3..e2c1107 100644
--- a/gpu/command_buffer/client/BUILD.gn
+++ b/gpu/command_buffer/client/BUILD.gn
@@ -40,6 +40,8 @@ component("client_sources_for_ppapi") {
 }
 
 source_set("client_sources") {
+  # External code should depend on this via //gpu/client above rather than
+  # depending on this directly or the component build will break.
   visibility = [ "//gpu/*" ]
 
   sources = [
diff --git a/gpu/command_buffer/service/BUILD.gn b/gpu/command_buffer/service/BUILD.gn
index 7ad6816..3b83386 100644
--- a/gpu/command_buffer/service/BUILD.gn
+++ b/gpu/command_buffer/service/BUILD.gn
@@ -18,10 +18,9 @@ group("service") {
 }
 
 source_set("service_sources") {
-  visibility = [
-    "//gpu/*",
-    "//mojo/gles2:gles2",
-  ]
+  # External code should depend on this via //gpu/command_buffer/service above
+  # rather than depending on this directly or the component build will break.
+  visibility = [ "//gpu/*" ]
 
   sources = [
     "buffer_manager.cc",
diff --git a/gpu/config/BUILD.gn b/gpu/config/BUILD.gn
index 3ca9edf..d0434ea 100644
--- a/gpu/config/BUILD.gn
+++ b/gpu/config/BUILD.gn
@@ -23,10 +23,9 @@ group("config") {
 }
 
 source_set("config_sources") {
-  visibility = [
-    "//components/mus/gles2:*",
-    "//gpu/*",
-  ]
+  # External code should depend on this via //gpu/config above rather than
+  # depending on this directly or the component build will break.
+  visibility = [ "//gpu/*" ]
 
   sources = [
     "dx_diag_node.cc",
diff --git a/gpu/ipc/common/BUILD.gn b/gpu/ipc/common/BUILD.gn
index 074f7d9..c596e26 100644
--- a/gpu/ipc/common/BUILD.gn
+++ b/gpu/ipc/common/BUILD.gn
@@ -29,6 +29,9 @@ group("command_buffer_traits") {
 }
 
 source_set("command_buffer_traits_sources") {
+  # External code should depend on this via
+  # //gpu/ipc/common:command_buffer_traits above rather than depending on this
+  # directly or the component build will break.
   visibility = [ "//gpu/*" ]
 
   sources = [
@@ -51,6 +54,8 @@ source_set("command_buffer_traits_sources") {
 }
 
 source_set("ipc_common_sources") {
+  # External code should depend on this via //gpu/ipc/common above rather than
+  # depending on this directly or the component build will break.
   visibility = [ "//gpu/*" ]
 
   sources = [
@@ -81,7 +86,7 @@ source_set("ipc_common_sources") {
     "//gpu/command_buffer/common:common_sources",
     "//gpu/config:config_sources",
     "//ipc",
-    "//ui/events/ipc:events_ipc",
+    "//ui/events/ipc",
     "//ui/gfx/ipc",
     "//ui/gl",
     "//url/ipc:url_ipc",
diff --git a/media/BUILD.gn b/media/BUILD.gn
index 84e0b03..efe4d1a 100644
--- a/media/BUILD.gn
+++ b/media/BUILD.gn
@@ -722,9 +722,11 @@ source_set("test_support") {
     "video/mock_video_decode_accelerator.cc",
     "video/mock_video_decode_accelerator.h",
   ]
-  deps = [
+  public_deps = [
     ":media",
     ":shared_memory_support",
+  ]
+  deps = [
     "//base",
     "//skia",
     "//testing/gmock",
diff --git a/mojo/gles2/BUILD.gn b/mojo/gles2/BUILD.gn
index 0fb54c1..705a8eb 100644
--- a/mojo/gles2/BUILD.gn
+++ b/mojo/gles2/BUILD.gn
@@ -56,7 +56,7 @@ component("gles2") {
   ]
 
   if (!is_component_build) {
-    deps += [ "//gpu/command_buffer/service:service_sources" ]
+    deps += [ "//gpu/command_buffer/service" ]
   }
 
   include_dirs = [ ".." ]
diff --git a/ppapi/proxy/BUILD.gn b/ppapi/proxy/BUILD.gn
index 66cb384..1e41208 100644
--- a/ppapi/proxy/BUILD.gn
+++ b/ppapi/proxy/BUILD.gn
@@ -362,6 +362,9 @@ source_set("test_support") {
     "resource_message_test_sink.h",
   ]
 
+  public_deps = [
+    ":proxy",
+  ]
   deps = [
     "//base/test:test_support",
     "//ipc",
diff --git a/ppapi/shared_impl/BUILD.gn b/ppapi/shared_impl/BUILD.gn
index 6fbb136..67bd069 100644
--- a/ppapi/shared_impl/BUILD.gn
+++ b/ppapi/shared_impl/BUILD.gn
@@ -207,12 +207,14 @@ source_set("test_support") {
     "test_utils.h",
   ]
 
+  public_deps = [
+    "//ppapi/shared_impl",
+  ]
   deps = [
     "//base/test:test_support",
     "//ipc",
     "//ipc:test_support",
     "//ppapi/proxy",
-    "//ppapi/shared_impl",
     "//testing/gmock",
     "//testing/gtest",
   ]
diff --git a/ui/events/BUILD.gn b/ui/events/BUILD.gn
index 44087eb..20b75f2 100644
--- a/ui/events/BUILD.gn
+++ b/ui/events/BUILD.gn
@@ -404,7 +404,7 @@ test("events_unittests") {
       "//third_party/WebKit/public:blink_headers",
       "//ui/events/blink",
       "//ui/events/gestures/blink",
-      "//ui/events/ipc:events_ipc",
+      "//ui/events/ipc",
     ]
   }
 
diff --git a/ui/events/ipc/BUILD.gn b/ui/events/ipc/BUILD.gn
index 975b875..b6ccbf5 100644
--- a/ui/events/ipc/BUILD.gn
+++ b/ui/events/ipc/BUILD.gn
@@ -4,7 +4,7 @@
 
 import("//build/config/ui.gni")
 
-component("events_ipc") {
+component("ipc") {
   output_name = "events_ipc"
   sources = [
     "latency_info_param_traits.cc",