More strict restrictions for content -> content/shell dependencies.

content/DEPS

 # Do NOT add chrome to the list below. We shouldn't be including files
 # from src/chrome in src/content. Also, we may only depend on files in
 # src/components that are shared with the mojo html_viewer.
 include_rules = [
   # The subdirectories in content/ will manually allow their own include
   # directories in content/ so we disallow all of them.
   "-content",
   "+content/app/resources/grit/content_resources.h",
   "+content/common",
   "+content/grit",
   "+content/public/common",
   "+content/public/test",
-  "+content/shell",  # for content_browsertests
   "+content/test",
 
   "+blink",
 
   "+cc",
   "-cc/blink",
   # If you want to use any of these files, move them to src/base first.
   "-cc/base/scoped_ptr_algorithm.h",
   "-cc/base/scoped_ptr_deque.h",
   "-cc/base/scoped_ptr_vector.h",
@@ skipping 81 matching lines @@
   # line, since the top level DEPS doesn't allow it, we add it to make this
   # explicit.
   "-ui/views",
 
   "+storage/browser",
   "+storage/common",
 
   # For generated JNI includes.
   "+jni",
 ]
+
+# content -> content/shell dependency is not allowed, except for browser tests.
+specific_include_rules = {
+    ".*_browsertest[a-z_]*\.cc": [
+    "+content/shell/browser",
+    "+content/shell/common",
+  ],
+}
+