Add browser_tests to the GN build.

Other misc fixes including:

Add "data_deps" to the templates in BUILDCONFIG. This was renamed from "datadeps" a while ago but both are still supported.

extension_management_test_util.cc includes a generated file policy_constants. GYP generates this with an extra "policy" directory but GN doesn't. The way GYP has the dirs set up, though, using only one "policy" works (and this is what other files do) so I just changed the include.

TBR=dpranke

Review URL: https://codereview.chromium.org/824373003

Cr-Original-Commit-Position: refs/heads/master@{#310276}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 7d6ec24650eb3f6c7ab8dcfcf0c2829095951962

config/BUILDCONFIG.gn

@@ -561,6 +561,9 @@ template("component") {
       if (defined(invoker.data)) {
         data = invoker.data
       }
+      if (defined(invoker.data_deps)) {
+        data_deps = invoker.data_deps
+      }
       if (defined(invoker.datadeps)) {
         datadeps = invoker.datadeps
       }
@@ -656,6 +659,9 @@ template("component") {
       if (defined(invoker.data)) {
         data = invoker.data
       }
+      if (defined(invoker.data_deps)) {
+        data_deps = invoker.data_deps
+      }
       if (defined(invoker.datadeps)) {
         datadeps = invoker.datadeps
       }
@@ -758,6 +764,9 @@ template("test") {
       if (defined(invoker.data)) {
         data = invoker.data
       }
+      if (defined(invoker.data_deps)) {
+        data_deps = invoker.data_deps
+      }
       if (defined(invoker.datadeps)) {
         datadeps = invoker.datadeps
       }
@@ -845,6 +854,9 @@ template("test") {
       if (defined(invoker.data)) {
         data = invoker.data
       }
+      if (defined(invoker.data_deps)) {
+        data_deps = invoker.data_deps
+      }
       if (defined(invoker.datadeps)) {
         datadeps = invoker.datadeps
       }