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}

1 files changed, 13 insertions, 0 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/*",